Are tactile function and body awareness of the foot related to motor outcomes in children with upper motor neuron lesions?

Introduction

Somatosensory function can be reduced in children with Upper Motor Neuron (UMN) lesions. Therefore, we investigated relationships between somatosensory functions of the foot and motor outcomes in children with UMN lesions.

Method

In this cross-sectional study, we assessed the Tactile Threshold (TT) with monofilaments and body awareness with Tactile Localisation Tasks for spatial-related action (TLTaction) and structural-related perception (TLTperception) body representation at the foot sole. Furthermore, we assessed four motor outcomes: the Selective Control Assessment of the Lower Extremity (SCALE), the modified Timed Up and Go test (mTUG), the Gillette Functional Assessment Questionnaire (FAQ), and the Functional Mobility Scale (FMS). Spearman's correlations (ρ) were applied to assess relationships between the somatosensory function of the foot sole and the applied motor outcomes.

Results

Thirty-five children with UMN lesions, on average 11.7 ± 3.4 years old, participated. TLTperception correlated significantly with all lower limb motor outcomes (|ρ|=0.36-0.57; p < 0.05), but TLTaction (|ρ|=0.00-0.27; p = 0.15-0.97, and TT did not (|ρ|=0.01-0.83; p = 0.73-0.94). TLTperception correlated strongly with the Gross Motor Function Classification System (|ρ|=0.62; p = 0.001) in children with cerebral palsy (n = 24).

Discussion

Assessing structural body representation of the foot sole should be considered when addressing lower limb motor impairments, including gait, in children with upper motor neuron lesions. Our results suggest that the assessment of tactile function and spatial body representation may be less related to lower limb motor function.

A Randomized Trial of Intravenous Iron Supplementation and Exercise on Exercise Capacity in Iron-Deficient Nonanemic Patients With CKD

Introduction

Patients with chronic kidney disease (CKD) are often iron deficient, even when not anemic. This trial evaluated whether iron supplementation enhances exercise capacity of nonanemic patients with CKD who have iron-deficiency.

Methods

Prospective, multicenter double-blind randomized controlled trial of nondialysis patients with CKD and iron-deficiency but without anemia (Hemoglobin [Hb] >110 g/l). Patients were assigned 1:1 to intravenous (IV) iron therapy, or placebo. An 8-week exercise program commenced at week 4. The primary outcome was the mean between-group difference in 6-minute walk test (6MWT) at 4 weeks. Secondary outcomes included 6MWT at 12 weeks, transferrin saturation (TSAT), serum ferritin (SF), Hb, renal function, muscle strength, functional capacity, quality of life, and adverse events at baseline, 4 weeks, and at 12 weeks. Mean between-group differences were analyzed using analysis of covariance models.

Results

Among 75 randomized patients, mean (SD) age for iron therapy (n = 37) versus placebo (n = 38) was 54 (16) versus 61 (12) years; estimated glomerular filtration rate (eGFR) (34 [12] vs. 35 [11] ml/min per 1.73 m2], TSAT (23 [12] vs. 21 [6])%; SF (57 [64] vs. 62 [33]) μg/l; Hb (122.4 [9.2] vs. 127 [13.2] g/l); 6MWT (384 [95] vs. 469 [142] meters) at baseline, respectively. No significant mean between-group difference was observed in 6MWT distance at 4 weeks. There were significant increases in SF and TSAT at 4 and 12 weeks (P < 0.02), and Hb at 12 weeks (P = 0.009). There were no between-group differences in other secondary outcomes and no adverse events attributable to iron therapy.

Conclusion

This trial did not demonstrate beneficial effects of IV iron therapy on exercise capacity at 4 weeks. A larger study is needed to confirm if IV iron is beneficial in nondialysis patients with CKD who are iron-deficient.

Use of a wearable accelerometer to evaluate physical frailty in people receiving haemodialysis

BACKGROUND

Physical frailty is a major health concern among people receiving haemodialysis (HD) for stage-5 chronic kidney disease (CKD-5). Wearable accelerometers are increasingly being recommended to objectively monitor activity levels in CKD-5 and recent research suggests they may also represent an innovative strategy to evaluate physical frailty in vulnerable populations. However, no study has yet explored whether wearable accelerometers may be utilised to assess frailty in the context of CKD-5-HD. Therefore, we aimed to examine the diagnostic performance of a research-grade wearable accelerometer in evaluating physical frailty in people receiving HD.

METHODS

Fifty-nine people receiving maintenance HD [age = 62.3 years (SD = 14.9), 40.7% female] participated in this cross-sectional study. Participants wore a uniaxial accelerometer (ActivPAL) for seven consecutive days and the following measures were recorded: total number of daily steps and sit-to-stand transitions, number of daily steps walked with cadence < 60 steps/min, 60-79 steps/min, 80-99 steps/min, 100-119 steps/min, and ≥ 120 steps/min. The Fried phenotype was used to evaluate physical frailty. Receiver operating characteristics (ROC) analyses were performed to examine the diagnostic accuracy of the accelerometer-derived measures in detecting physical frailty status.

RESULTS

Participants classified as frail (n = 22, 37.3%) had a lower number of daily steps (2363 ± 1525 vs 3585 ± 1765, p = 0.009), daily sit-to-stand transitions (31.8 ± 10.3 vs 40.6 ± 12.1, p = 0.006), and lower number of steps walked with cadence of 100-119 steps/min (336 ± 486 vs 983 ± 797, p < 0.001) compared to their non-frail counterparts. In ROC analysis, the number of daily steps walked with cadence ≥ 100 steps/min exhibited the highest diagnostic performance (AUC = 0.80, 95% CI: 0.68-0.92, p < 0.001, cut-off ≤ 288 steps, sensitivity = 73%, specificity = 76%, PPV = 0.64, NPV = 0.82, accuracy = 75%) in detecting physical frailty.

CONCLUSIONS

This study provided initial evidence that a wearable accelerometer may be a useful tool in evaluating physical frailty in people receiving HD. While the total number of daily steps and sit-to-stand transitions could significantly discriminate frailty status, the number of daily steps walked with cadences reflecting moderate to vigorous intensity of walking may be more useful in monitoring physical frailty in people receiving HD.

Feasibility of randomized controlled trials and long-term implementation of interventions: Insights from a qualitative process evaluation of the PEDAL trial

Introduction

A multi-site randomized controlled trial was carried out between 2015 and 2019 to evaluate the impacts on quality of life of an intradialytic exercise programme for people living with chronic kidney disease. This included a qualitative process evaluation which gave valuable insights in relation to feasibility of the trial and of the intervention in the long-term. These can inform future clinical Trial design and evaluation studies.

Methods

A constructivist phenomenological approach underpinned face-to-face, semi-structured interviews. Purposive recruitment ensured inclusion of participants in different arms of the PEDAL Trial, providers with different roles and trial team members from seven Renal Units in five study regions. Following ethical review, those willing took part in one interview in the Renal Unit. Audio-recorded interviews were transcribed (intelligent verbatim) and inductively thematically analyzed.

Results

Participants (n = 65) (Intervention arm: 26% completed; 13% who did not; Usual care arm: 13%; 46% women; 54% men; mean age 60 year) and providers (n = 39) were interviewed (23% PEDAL Trial team members). Three themes emerged: (1) Implementing the Intervention; (2) Implementing the trial; and (3) Engagement of the clinical team. Explanatory theory named "the Ideal Scenario" was developed, illustrating complex interactions between different aspects of intervention and trial implementation with the clinical context. This describes characteristics likely to optimize trial feasibility and intervention sustainability in the long-term. Key aspects of this relate to careful integration of the trial within the clinical context to optimize promotion of the trial in the short-term and engagement and ownership in the long-term. Strong leadership in both the clinical and trial teams is crucial to ensure a proactive and empowering culture.

Conclusion

Novel explanatory theory is proposed with relevance for Implementation Science. The "Ideal Scenario" is provided to guide trialists in pre-emptive and ongoing risk analysis relating to trial feasibility and long-term intervention implementation. Alternative study designs should be explored to minimize the research-to-practice gap and optimize the likelihood of informative findings and long-term implementation. These might include Realist Randomized Controlled Trials and Hybrid Effectiveness-Implementation studies.

The effect of intravenous iron supplementation on exercise capacity in iron-deficient but not anaemic patients with chronic kidney disease: study design and baseline data for a multicentre prospective double-blind randomised controlled trial

BACKGROUND

Many people living with chronic kidney disease (CKD) are iron deficient, even though they may not be anaemic. The Iron and Muscle study aims to evaluate whether iron supplementation reduces symptoms of fatigue, improves muscle metabolism, and leads to enhanced exercise capacity and physical function. We report here the trial design and baseline characteristics.

METHODS

This is a prospective, double-blind multicentre randomised controlled trial (RCT) including 75 non-dialysis stage 3-4 CKD patients with iron deficiency but without anaemia. Patients were randomly (1:1) assigned to either: i) intravenous iron therapy, or ii) placebo, with concurrent recruitment of eight CKD non-iron deficient participants and six healthy volunteers. The primary outcome of the study is the six-minute walk test (6MWT) distance between baseline and four-weeks. An additional exercise training programme for patients in both groups was initiated and completed between 4 and 12 weeks, to determine the effect of iron repletion compared to placebo treatment in the context of patients undertaking an exercise programme. Additional secondary outcomes include fatigue, physical function, muscle strength, muscle metabolism, quality of life, resting blood pressure, clinical chemistry, safety and harms associated with the iron therapy intervention and the exercise training intervention, and hospitalisations. All outcomes were conducted at baseline, 4, and 12 weeks, with a nested qualitative study, to investigate the experience of living with iron deficiency and intervention acceptability. The cohort have been recruited and baseline assessments undertaken.

RESULTS

Seventy-five individuals were recruited. 44% of the randomised cohort were male, the mean (SD) age was 58 (14) years, and 56% were White. Body mass index was 31 (7) kg/m²; serum ferritin was 59 (45) μg/L, transferrin saturation was 22 (10) %, and haemoglobin was 125 (12) g/L at randomisation for the whole group. Estimated glomerular filtration rate was 35 (12) mL/min/1.73 m² and the baseline 6MWT distance was 429 (174) m.

CONCLUSION

The results from this study will address a substantial knowledge gap in the effects of intravenous iron therapy, and offer potential clinical treatment options, to improve exercise capacity, physical function, fatigue, and muscle metabolism, for non-dialysis patients with CKD who are iron-deficient but not anaemic. It will also offer insight into the potential novel effects of an 8-week exercise training programme.

TRIAL REGISTRATION

EudraCT: 2018-000,144-25 Registered 28/01/2019.

Resistance Exercise in People With Stage-3 Chronic Kidney Disease: Effects of Training Frequency (Weekly Volume) on Measures of Muscle Wasting and Function

Background: Resistance training (RT) is a proven anabolic intervention in people living with and without chronic kidney disease (CKD). To date, there is a dearth of knowledge regarding the dose-response relationship of RT in the non-dialysis dependent CKD population. Therefore, we aimed to explore the effects of RT frequency (weekly volume) on established measures of muscle wasting and function in CKD.

Methods: Twenty people with stage-3 CKD (CKD-3) were allocated to either a low frequency (one-session per week, RT1) or higher frequency (three-sessions per week, RT3) 12-week RT programme consisting of lower extremity strengthening exercises. The two RT programmes were not volume matched. Assessment outcomes before and after the intervention included measures of total and regional body composition, muscle size and architecture, strength, physical function, and uraemic symptoms.

Results: Significant improvements over time in muscle size and architecture, strength, physical function, and uraemic symptoms were observed for both RT1 and RT3. Compared to RT1, participants who performed RT3 showed greater increases in vastus lateralis (VL) anatomical cross-sectional area (30.8% vs. 13.2%, p < 0.001) and pennation angle (36.3% vs. 17.5%, p = 0.008) after 12 weeks. In either group, there were no significant changes over time in mid-VL fascicle length, nor in measures of total body composition and upper arm muscle strength.

Conclusion: Despite the group differences observed in the VL physiological adaptations, the strength and physical function responses, as well as the reductions of uraemic symptoms, were similar whether training once or thrice weekly. Therefore, performing RT just once per week may be an effective pre-habilitation strategy for people with CKD-3.

Leisure Time Physical Activity in Children and Young People With Cerebral Palsy: A Population-Based Study

PURPOSE

To describe leisure time physical activity in children and young people with cerebral palsy and identify barriers and facilitators to participation.

METHODS

Leisure time physical activity participation was derived from a national cerebral palsy register and associated factors were analyzed. Barriers and facilitators to participation were investigated through a survey.

RESULTS

Leisure time physical activity participation was recorded. Outcomes of participation decreased with increasing Gross Motor Function Classification System level. Leisure time physical activity "not in club" for 11- to 18-year-olds was significantly lower than for those aged 5 to 10 years for Gross Motor Function Classification System level II. The survey supported that disability and disliking help were common barriers and parental encouragement and enjoyment were common facilitators.

CONCLUSIONS

Data from the register and survey provide insight into factors influencing leisure time physical activity participation in young people with cerebral palsy and how to increase.

Screening tools to expedite assessment of frailty in people receiving haemodialysis: a diagnostic accuracy study

BACKGROUND

Frailty is associated with multiple adverse outcomes in stage-5 chronic kidney disease (CKD-5) and upwards of one third of people receiving haemodialysis (HD) are frail. While many frailty screening methods are available in both uremic and non-uremic populations, their implementation in clinical settings is often challenged by time and resource constraints. In this study, we explored the diagnostic accuracy of time-efficient screening tools in people receiving HD.

METHODS

A convenience sample of 76 people receiving HD [mean age = 61.1 years (SD = 14), 53.9% male] from three Renal Units were recruited for this cross-sectional study. Frailty was diagnosed by means of the Fried phenotype. Physical performance-based screening tools encompassed handgrip strength, 15-ft gait speed, timed up and go (TUG), and five-repetition sit to stand (STS-5) tests. In addition, participants completed the SF-36 Health Survey, the short-form international physical activity questionnaire and the Tinetti falls efficacy scale (FES) as further frailty-related measures. Outcome measures included the area under the curve (AUC), sensitivity, specificity, positive (PPV) and negative predictive values (NPV). The diagnostic performance of screening tools in assessing fall-risk was also investigated.

RESULTS

Overall, 36.8% of participants were classified as frail. All the examined instruments could significantly discriminate frailty status in the study population. Gait speed [AUC = 0.89 (95%CI: 0.81-0.98), sensitivity = 75%, specificity = 93%] and TUG [AUC = 0.90 (95%CI: 0.80-0.99), sensitivity = 89%, specificity = 85%] exhibited the highest diagnostic accuracy. There was a significant difference in gait speed AUC (20%, p = 0.013) between participants aged 65 years or older (n = 36) and those under 65 years of age (n = 40), with better discriminating performance in the younger sub-group. The Tinetti FES was the only instrument showing good diagnostic accuracy (AUCs≥0.80) for both frailty (sensitivity = 82%, specificity = 79%) and fall-risk (sensitivity = 82%, specificity = 71%) screening.

CONCLUSIONS

This cross-sectional study revealed that time- and cost-efficient walking performance measures can accurately be used for frailty-screening purposes in people receiving HD. While self-selected gait speed had an excellent performance in people under 65 years of age, TUG may be a more suitable screening method for elderly patients (≥65 years). The Tinetti FES may be a clinically useful test when physical testing is not achievable.

Exercise programme to improve quality of life for patients with end-stage kidney disease receiving haemodialysis: the PEDAL RCT

BACKGROUND

Whether or not clinically implementable exercise interventions in haemodialysis patients improve quality of life remains unknown.

OBJECTIVES

The PEDAL (PrEscription of intraDialytic exercise to improve quAlity of Life in patients with chronic kidney disease) trial evaluated the clinical effectiveness and cost-effectiveness of a 6-month intradialytic exercise programme on quality of life compared with usual care for haemodialysis patients.

DESIGN

We conducted a prospective, multicentre randomised controlled trial of haemodialysis patients from five haemodialysis centres in the UK and randomly assigned them (1 : 1) using a web-based system to (1) intradialytic exercise training plus usual-care maintenance haemodialysis or (2) usual-care maintenance haemodialysis.

SETTING

The setting was five dialysis units across the UK from 2015 to 2019.

PARTICIPANTS

The participants were adult patients with end-stage kidney disease who had been receiving haemodialysis therapy for > 1 year.

INTERVENTIONS

Participants were randomised to receive usual-care maintenance haemodialysis or usual-care maintenance haemodialysis plus intradialytic exercise training.

MAIN OUTCOME MEASURES

The primary outcome of the study was change in Kidney Disease Quality of Life Short Form, version 1.3, physical component summary score (from baseline to 6 months). Cost-effectiveness was determined using health economic analysis and the EuroQol-5 Dimensions, five-level version. Additional secondary outcomes included quality of life (Kidney Disease Quality of Life Short Form, version 1.3, generic multi-item and burden of kidney disease scales), functional capacity (sit-to-stand 60 and 10-metre Timed Up and Go tests), physiological measures (peak oxygen uptake and arterial stiffness), habitual physical activity levels (measured by the International Physical Activity Questionnaire and Duke Activity Status Index), fear of falling (measured by the Tinetti Falls Efficacy Scale), anthropometric measures (body mass index and waist circumference), clinical measures (including medication use, resting blood pressure, routine biochemistry, hospitalisations) and harms associated with intervention. A nested qualitative study was conducted.

RESULTS

We randomised 379 participants; 335 patients completed baseline assessments and 243 patients (intervention, n = 127; control, n = 116) completed 6-month assessments. The mean difference in change in physical component summary score from baseline to 6 months between the intervention group and control group was 2.4 arbitrary units (95% confidence interval -0.1 to 4.8 arbitrary units; p = 0.055). Participants in the intervention group had poor compliance (49%) and very poor adherence (18%) to the exercise prescription. The cost of delivering the intervention ranged from £463 to £848 per participant per year. The number of participants with harms was similar in the intervention (n = 69) and control (n = 56) groups.

LIMITATIONS

Participants could not be blinded to the intervention; however, outcome assessors were blinded to group allocation.

CONCLUSIONS

On trial completion the primary outcome (Kidney Disease Quality of Life Short Form, version 1.3, physical component summary score) was not statistically improved compared with usual care. The findings suggest that implementation of an intradialytic cycling programme is not an effective intervention to enhance health-related quality of life, as delivered to this cohort of deconditioned patients receiving haemodialysis.

FUTURE WORK

The benefits of longer interventions, including progressive resistance training, should be confirmed even if extradialytic delivery is required. Future studies also need to evaluate whether or not there are subgroups of patients who may benefit from this type of intervention, and whether or not there is scope to optimise the exercise intervention to improve compliance and clinical effectiveness.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN83508514.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 40. See the NIHR Journals Library website for further project information.

Randomized Trial-PrEscription of intraDialytic exercise to improve quAlity of Life in Patients Receiving Hemodialysis

Introduction

Whether clinically implementable exercise interventions in people receiving hemodialysis (HD) therapy improve health-related quality of life (HRQoL) remains unknown. The PrEscription of intraDialytic exercise to improve quAlity of Life (PEDAL) study evaluated the clinical benefit and cost-effectiveness of a 6-month intradialytic exercise program.

Methods

In a multicenter, single-blinded, randomized, controlled trial, people receiving HD were randomly assigned to (i) intradialytic exercise training (exercise intervention group [EX]) and (ii) usual care (control group [CON]). Primary outcome was change in Kidney Disease Quality of Life Short-Form Physical Component Summary (KDQOL-SF 1.3 PCS) from baseline to 6 months. Cost-effectiveness was determined using health economic analysis; physiological impairment was evaluated by peak oxygen uptake; and harms were recorded.

Results

We randomized 379 participants; 335 and 243 patients (EX n = 127; CON n = 116) completed baseline and 6-month assessments, respectively. Mean difference in change PCS from baseline to 6 months between EX and CON was 2.4 (95% confidence interval [CI]: -0.1 to 4.8) arbitrary units (P = 0.055); no improvements were observed in peak oxygen uptake or secondary outcome measures. Participants in the intervention group had poor compliance (47%) and poor adherence (18%) to the exercise prescription. Cost of delivering intervention ranged from US$598 to US$1092 per participant per year. The number of participants with harms was similar between EX (n = 69) and CON (n = 56). A primary limitation was the lack of an attention CON. Many patients also withdrew from the study or were too unwell to complete all physiological outcome assessments.

Conclusions

A 6-month intradialytic aerobic exercise program was not clinically beneficial in improving HRQoL as delivered to this cohort of deconditioned patients on HD.

Validity and reliability of high-resolution ultrasound imaging for the assessment of regional body composition in stage 5 chronic kidney disease patients undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Accurate measurement of muscle mass is an important research and clinical tool. High-resolution ultrasound (US) has shown potential as a method to assess muscle and fat mass at specific anatomical sites. However, there is limited evidence for the reliability of US to measure muscle size in patients receiving continuous ambulatory peritoneal dialysis (CAPD). Therefore, we examined the validity and reliability of an US method compared to a gold standard comparison for the assessment of a quadriceps muscle in this clinical population.

METHODS

Twenty people receiving CAPD (mean age = 56.5 ± 16.7 years) at a single dialysis unit were assessed on two occasions, 7 days apart. Measures of the mid-thigh, such as vastus lateralis (VL) anatomical cross-sectional area (ACSA), VL muscle thickness and subcutaneous fat thickness were compared for US reliability and validity compared to magnetic resonance imaging (MRI) measures.

RESULTS

US had high validity against gold standard MRI measures, with intraclass correlation coefficients (ICC) equating to VL ACSA of 0.95, VL thickness of 0.99 and fat thickness of 0.98. The US measurements also exhibited high intra-rater reliability (ICCs: VL thickness = 0.98, total muscle thickness = 0.97 and fat thickness = 0.99) in measuring body composition at the mid-VL site in the study population.

CONCLUSIONS

Valid assessment of regional body composition can be achieved via high-resolution US in patients receiving CAPD. The validity and reliability of the US in repeated measures (in comparison to the gold standard MRI) warrant further investigation in the wider chronic kidney disease population.

Exercise-induced changes in gait kinematics in multiple sclerosis with minimal neurological disability

BACKGROUND

Exercise-induced gait deterioration is a frequently encountered symptom that limits ambulation throughout the clinical course, becoming more prominent with increasing neurological disability in people with MS (pwMS).

OBJECTIVE

We attempted to objectively document exercise-induced gait changes in pwMS with minimal neurological disability and stable disease.

METHODS

Gait kinematics and spatio-temporal parameters were recorded using 3D motion analysis before and after a 20-minute treadmill walk (Group A, n=15)/run (Group B, n=15) at a self-selected speed in pwMS and compared with healthy controls (n=15).

RESULTS

Gait analysis revealed a significant decrease in peak ankle dorsiflexion in swing of the most affected leg, post-exercise task, in both Group A (EDSS 2.5-3.5) and Group B (EDSS 1-2.5) and not in healthy controls. Fourteen out of 30 MS participants showed an exercise-induced gait deterioration, based on minimal detectable change. Pre-exercise gait parameters in Group A showed a significantly higher peak dorsiflexion in swing with shorter step length and higher cadence, whereas Group B was comparable to healthy controls.

CONCLUSION

The detection of exercise-induced gait deterioration (foot drop) in pwMS with minimal neurological disability and stable disease indicates the potential of gait kinematics, before and after an exercise task, to monitor subtle neurological deficits from an early stage of MS.

Association of postural balance and falls in adult patients receiving haemodialysis: A prospective cohort study

BACKGROUND

Static postural balance performance is often impaired in people receiving haemodialysis (HD) for the treatment of stage-5 chronic kidney disease (CKD-5). However, the question as to whether lower postural balance is associated with adverse clinical outcomes such as falls has not been addressed yet.

RESEARCH QUESTION

We conducted a prospective cohort study to explore the association between static postural balance and falls in people receiving HD. We hypothesised that higher postural sway would be associated with increased odds of falling.

METHODS

Seventy-five prevalent CKD-5 patients receiving HD (age: 61.8 ± 13.4 years) from three Renal Units were enrolled in this prospective cohort study. At baseline, postural balance was assessed with a force platform in eyes open (EO) and eyes closed (EC) conditions. Centre of pressure (CoP) measures of range, velocity and area were taken for the analysis. Falls experienced by study participants were prospectively recorded during 12 months of follow-up. Secondary outcomes included timed-up and go, five-repetition sit-to-stand test and the Tinetti falls efficacy scale (FES).

RESULTS

In multivariable logistic regression analysis, higher CoP range in medial-lateral direction during EC was associated with increased odds of falling (OR: 1.04, 95 %CI: 1.00-1.07, p = 0.036). In ROC curve analysis, CoP velocity in EO exhibited the greatest prognostic accuracy (AUC: 0.69, 95 %CI: 0.55-0.82), however this was not statistically different from CoP measures of area and range. None of the postural balance measures exceeded the prognostic accuracy of the FES (AUC: 0.70, 95 %CI: 0.58-0.83, p = 0.005).

SIGNIFICANCE

This prospective cohort study showed that higher postural sway in medial-lateral direction was associated with increased odds of falling in people receiving HD. CoP measures of range, velocity and area displayed similar prognostic value in discriminating fallers from non-fallers. The overall utility of static posturography to detect future fall-risk may be limited in a clinical setting.

The PrEscription of intraDialytic exercise to improve quAlity of Life in patients with chronic kidney disease trial: study design and baseline data for a multicentre randomized controlled trial

Background

Exercise interventions designed to improve physical function and reduce sedentary behaviour in haemodialysis (HD) patients might improve exercise capacity, reduce fatigue and lead to improved quality of life (QOL). The PrEscription of intraDialytic exercise to improve quAlity of Life study aimed to evaluate the effectiveness of a 6-month intradialytic exercise programme on QOL and physical function, compared with usual care for patients on HD in the UK.

Methods

We conducted a prospective, pragmatic multicentre randomized controlled trial in 335 HD patients and randomly (1:1) assigned them to either (i) intradialytic exercise training plus usual care maintenance HD or (ii) usual care maintenance HD. The primary outcome of the study was the change in Kidney Disease Quality of Life Short Form (KDQOL-SF 1.3) Physical Component Score between baseline and 6 months. Additional secondary outcomes included changes in peak aerobic capacity, physical fitness, habitual physical activity levels and falls (International Physical Activity Questionnaire, Duke’s Activity Status Index and Tinetti Falls Efficacy Scale), QOL and symptom burden assessments (EQ5D), arterial stiffness (pulse wave velocity), anthropometric measures, resting blood pressure, clinical chemistry, safety and harms associated with the intervention, hospitalizations and cost-effectiveness. A nested qualitative study investigated the experience and acceptability of the intervention for both participants and members of the renal health care team.

Results

At baseline assessment, 62.4% of the randomized cohort were male, the median age was 59.3 years and 50.4% were white. Prior cerebrovascular events and myocardial infarction were present in 8 and 12% of the cohort, respectively, 77.9% of patients had hypertension and 39.4% had diabetes. Baseline clinical characteristics and laboratory data for the randomized cohort were generally concordant with data from the UK Renal Registry.

Conclusion

The results from this study will address a significant knowledge gap in the prescription of exercise interventions for patients receiving maintenance HD therapy and inform the development of intradialytic exercise programmes both nationally and internationally.

Trial Registration

ISRCTN N83508514; registered on 17 December 2014.

Minimum accelerometer wear-time for reliable estimates of physical activity and sedentary behaviour of people receiving haemodialysis

BACKGROUND

Low levels of physical activity are implicated in low life expectancies of people receiving maintenance haemodialysis. Accelerometers are increasingly being used to quantify activity behaviours of this population but guidance to quality-assure such data is lacking. The objective of this study was to provide data processing and reduction recommendations to ensure accelerometer-derived outcomes are sufficiently reliable for interpretative analysis.

METHODS

Seventy people receiving maintenance haemodialysis (age 55.9 ± 15.7 years, 34% women, 23% diabetic) from a single outpatient renal unit volunteered for the study. Participants wore Actigraph GT3x and ActivPAL monitors during waking hours over seven days. Reliability of accelerometer output (normalised to wear-time) was assessed via intraclass correlation coefficient (ICC). The Spearman-Brown prophecy formula was subsequently applied to the ICCs to derive the minimum required accelerometer wear-time for each behavioural outcome.

RESULTS

Monitor wear compliance was greater on dialysis compared to non-dialysis days (90% v 77%). Participants were significantly more active on non-dialysis days compared to dialysis days but there were no significant differences in estimated behaviours between days within the same condition. Average measure ICCs for all accelerometer outcomes were high (range 0.76-0.96). Computations indicated that habitual physical activity and sedentary behaviour could be estimated with a minimum reliability level of 0.80 from one dialysis day and two non-dialysis days, and at least eight hours monitor wear per day. Applying this rubric allowed 90% of participant data to be retained for further analysis.

CONCLUSIONS

Regardless of accelerometer, one dialysis and two non-dialysis days data with a minimum of eight hours wear each day should enable habitual activity of people receiving maintenance haemodialysis to be characterised with acceptable reliability. These recommendations reconcile the tension between wear-time criteria stringency and retention of an adequately representative sample.

Baroreflex function, haemodynamic responses to an orthostatic challenge, and falls in haemodialysis patients

BACKGROUND

Stage 5 chronic kidney disease patients on haemodialysis (HD) often present with dizziness and pre-syncopal events as a result of the combined effect of HD therapy and cardiovascular disease. The dysregulation of blood pressure (BP) during orthostasis may be implicated in the aetiology of falls in these patients. Therefore, we explored the relationship between baroreflex function, the haemodynamic responses to a passive orthostatic challenge, and falls in HD patients.

METHODS

Seventy-six HD patients were enrolled in this cross-sectional study. Participants were classified as "fallers" and "non-fallers" and completed a passive head up tilting to 60o (HUT-60°) test on an automated tilt table. ECG signals, continuous and oscillometric BP measurements and impedance cardiography were recorded. The following variables were derived from these measurements: heart rate (HR) stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), number of baroreceptor events, and baroreceptor effectiveness index (BEI).

RESULTS

The forty-four participants who were classified as fallers (57.9%) had a lower number of baroreceptor events (6.5±8.5 vs 14±16.7, p = .027) and BEI (20.8±24.2% vs 33.4±23.3%, p = .025). In addition, fallers experienced a significantly larger drop in systolic (-6.4±10.9 vs -0.4±7.7 mmHg, p = .011) and diastolic (-2.7±7.3 vs 1.8±6 mmHg, p = .027) oscillometric BP from supine to HUT-60° compared with non-fallers. None of the variables taken for the analysis were significantly associated with falls in multivariate logistic regression analysis.

CONCLUSIONS

This cross-sectional comparison indicates that, at rest, HD patients with a positive history of falls present with a lower count of baroreceptor sequences and BEI. Short-term BP regulation warrants further investigation as BP drops during a passive orthostatic challenge may be implicated in the aetiology of falls in HD.

Walking measures to evaluate assistive technology for foot drop in multiple sclerosis: A systematic review of psychometric properties

BACKGROUND

Foot drop in people with multiple sclerosis (pwMS) often managed with assistive technologies, such as functional electrical stimulation and ankle foot orthoses. No evidence synthesis exists for the psychometric properties of outcomes used to evaluate the efficacy of these interventions.

OBJECTIVE

This systematic review aimed to identify the outcome measures reported to assess the benefits of assistive technology for pwMS and then synthesize the psychometric evidence in pwMS for a subset of these measures.

METHODS

Two searches in eight databases were conducted up to May 2017. Methodological quality was rated using the COSMIN guidelines. Overall level of evidence was scored according to the Cochrane criteria.

RESULTS

The first search identified 27 measures, with the 10 m walk test, gait kinematics and Physiological Cost Index (PCI) most frequently used. The second search resulted in 41 studies evaluating 10 measures related to walking performance. Strong levels of evidence were found for the internal consistency and test-retest reliability of the Multiple Sclerosis Walking Scale-12 and for the construct validity for Timed 25 Foot Walk. No psychometric studies were identified for gait kinematics and PCI in pwMS. There was a lack of evidence for measurement error and responsiveness.

CONCLUSION

Although a strong level of evidence exists for some measures included in this review, there was an absence of psychometric studies on commonly used measures such as gait kinematics. Future psychometric studies should evaluate a wider range of walking related measures used to assess the efficacy of interventions to treat foot drop in pwMS.

Influence of trunk control and lower extremity impairments on gait capacity in children with cerebral palsy

PURPOSE

We investigated the combined impact of trunk control and lower extremities impairments on predicting gait capacity in children with cerebral palsy (CP) and evaluated relationships between trunk control and lower extremities impairments.

METHODS

Data of 52 children with CP [29 boys, mean age 11 years 9 months (±4 years 6 months)] were included in this observational study. Gait capacity was measured by the "modified Time Up and Go test". Experienced therapists performed the "Modified Ashworth Scale", "Manual Muscle Test", the "Selective Control Assessment of the Lower Extremity", and the "Trunk Control Measurement Scale". We calculated Spearman correlations coefficients (ρ) and performed regression analyses.

RESULTS

Trunk control was the strongest predictor (β = -0.624, p < 0.001) when explaining the variance of gait capacity and remained in the model together with spasticity (R² = 0.67). Muscle strength and selectivity correlated moderately to strongly with the trunk control and gait capacity (-0.68 ≤ ρ ≤ -0.78), but correlations for the spasticity were low (ρ<-0.3).

CONCLUSIONS

The interconnection between trunk control, leg muscle strength and selectivity for gait capacity in children with CP was shown. It indicates the significance of these impairments in gait assessment and, potentially, rehabilitation. Implications for Rehabilitation Trunk control was the strongest predictor for gait capacity in a regression model with lower extremity spasticity, muscle strength and selectivity and age as independent variables. Lower extremity muscle strength, selectivity, and trunk control explained a similar amount of gait capacity variance which is higher than that explained by lower extremity spasticity. Lower extremity muscle strength and selectivity correlated strongly with trunk control. Therefore, we cautiously suggest that a combined trunk control and lower extremity training might be promising for improving gait capacity in children with CP (Gross Motor Function Classification System level I-III), which needed to be tested in future intervention-studies.

Selective voluntary motor control measures of the lower extremity in children with upper motor neuron lesions: a systematic review

AIM

Recovery and trainability of impaired selective voluntary motor control (SVMC) of the lower extremity in children with upper motor neuron lesions has received little attention. To facilitate an evidence-based debate about this topic, this review evaluates the evidence level of the psychometric properties of SVMC measures.

METHOD

MEDLINE, Embase, CINAHL, PsycINFO, Scopus, Cochrane and PEDro databases were systematically searched up to July 2016. Two independent raters scored the methodological quality in accordance to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. The overall level of evidence was scored according to Cochrane criteria.

RESULTS

We identified 3590 studies, of which 17 were included. COSMIN scores ranged from 'poor' to 'excellent' for studies investigating measurement properties of the Selective Motor Control test, modified Trost test, Gillette's Selective Motor Control test, Selective Control Assessment of the Lower Extremity (SCALE), kinematic measures, electromyography, and torque steadiness. Studies assessing the SCALE scored highest on COSMIN items. Evidence levels for SCALE's validity and reliability properties were moderate, while for the other SVMC measures these ranged from unknown to moderate. Responsiveness was not assessed.

INTERPRETATION

Further psychometric studies of SVMC measures are needed to provide a scientific contribution to the ongoing debate of SVMC trainability.

Long-term pulse wave velocity outcomes with aerobic and resistance training in kidney transplant recipients - A pilot randomised controlled trial

BACKGROUND

This pilot study examined long-term pulse wave velocity (PWV) and peak oxygen uptake (VO2peak) outcomes following a 12-week moderate-intensity aerobic or resistance training programme in kidney transplant recipients.

METHOD

Single-blind, bi-centre randomised controlled parallel trial. 42 out of 60 participants completed a 9-month follow-up assessment (Aerobic training = 12, Resistance training = 10 and usual care = 20). Participants completed 12 weeks of twice-weekly supervised aerobic or resistance training. Following the 12-week exercise intervention, participants were transitioned to self-managed community exercise activity using motivational interviewing techniques. Usual care participants received usual encouragement for physical activity during routine clinical appointments in the transplant clinic. PWV, VO2peak, blood pressure and body weight were assessed at 12 weeks and 12 months, and compared to baseline.

RESULTS

ANCOVA analysis, covarying for baseline values, age, and length of time on dialysis pre-transplantation, revealed a significant mean between-group difference in PWV of -1.30 m/sec (95%CI -2.44 to -0.17, p = 0.03) between resistance training and usual care groups. When comparing the aerobic training and usual care groups at 9-month follow-up, there was a mean difference of -1.05 m/sec (95%CI -2.11 to 0.017, p = 0.05). A significant mean between-group difference in relative VO2peak values of 2.2 ml/kg/min (95% CI 0.37 to 4.03, p = 0.02) when comparing aerobic training with usual care was revealed. There was no significant between group differences in body weight or blood pressure. There were no significant adverse effects associated with the interventions.

CONCLUSIONS

Significant between-group differences in 9-month follow-up PWV existed when comparing resistance exercise intervention with usual care. A long-term between-group difference in VO2peak was only evident when comparing aerobic intervention with usual care. This pilot study, with a small sample size, did not aim to elucidate mechanistic mediators related to the exercise interventions. It is however suggested that a motivational interviewing approach, combined with appropriate transition to community training programmes, could maintain the improvements gained from the 12-week exercise interventions and further research in this area is therefore warranted.

TRIAL REGISTRATION

study number: ISRCTN43892586.

Construct validity and reliability of the Selective Control Assessment of the Lower Extremity in children with cerebral palsy

AIM

Assessing impaired selective voluntary movement control in children with cerebral palsy (CP) has gained increasing interest. We investigated construct validity and intra- and interrater reliability of the Selective Control Assessment of the Lower Extremity (SCALE).

METHOD

Thirty-nine children (21 males, 18 females) with spastic CP, mean age 12 years 6 months [range 6y 11mo-19y 9mo], Gross Motor Function Classification System (GMFCS) levels I to IV, participated. Differences in SCALE scores were determined on joint levels and between patients categorized according to their limb distribution and GMFCS levels. SCALE scores were correlated with the Fugl-Meyer Assessment, Manual Muscle Test, and Modified Ashworth Scale. To determine reliability, the SCALE was applied once and recorded on video.

RESULTS

SCALE scores differed significantly between the less and more affected leg (p<0.001) and between most leg joints. Total SCALE scores differed significantly between GMFCS levels I and II. Correlations with Fugl-Meyer Assessment, Manual Muscle Test, and Modified Ashworth Scale were 0.88, 0.88, and -0.55 respectively. Intraclass correlation coefficients were all above 0.9, with the minimal detectable change below 2 points.

INTERPRETATION

The SCALE appears to be a valid and reliable tool to assess selective voluntary movement control of the legs in children with spastic CP.

Aerobic or Resistance Training and Pulse Wave Velocity in Kidney Transplant Recipients: A 12-Week Pilot Randomized Controlled Trial (the Exercise in Renal Transplant [ExeRT] Trial)

BACKGROUND

Cardiovascular disease remains the leading cause of death in kidney transplant recipients. This pilot study examined the potential effect of aerobic training or resistance training on vascular health and indexes of cardiovascular risk in kidney transplant recipients.

STUDY DESIGN

Single-blind, randomized, controlled, parallel trial.

SETTING & PARTICIPANTS

60 participants (mean age, 54 years; 34 men) were randomly assigned to aerobic training (n=20), resistance training (n=20), or usual care (n=20). Participants were included if they had a kidney transplant within 12 months prior to baseline assessment. Patients were excluded if they had unstable medical conditions or had recently started regular exercise.

INTERVENTION

Aerobic training and resistance training were delivered 3 days per week for a 12-week period. The usual-care group received standard care.

OUTCOMES & MEASUREMENTS

Pulse wave velocity, peak oxygen uptake (Vo2peak), sit-to-stand 60, isometric quadriceps force, and inflammatory biomarkers were assessed at 0 and 12 weeks.

RESULTS

The anticipated 60 participants were recruited within 12 months. 46 participants completed the study (aerobic training, n=13; resistance training, n=13; and usual care, n=20), resulting in a 23% attrition rate. Analyses of covariance, adjusted for baseline values, age, and dialysis vintage pretransplantation, revealed significant mean differences between aerobic training and usual care in pulse wave velocity of -2.2±0.4 (95% CI, -3.1 to -1.3) m/s (P<0.001) and between resistance training and usual care of -2.6±0.4 (95% CI, -3.4 to -1.7) m/s (P<0.001) at 12 weeks. Secondary analyses indicated significant improvements in Vo2peak in the aerobic training group and in Vo2peak, sit-to-stand 60, and isometric muscle force in the resistance training group compared with usual care at 12 weeks. There were no reported adverse events, cardiovascular events, or hospitalizations as a result of the intervention.

LIMITATIONS

Pilot study, small sample size, no measure of endothelial function.

CONCLUSIONS

Both aerobic training and resistance training interventions appear to be feasible and clinically beneficial in this patient population.

Low-volume high-intensity interval training vs continuous aerobic cycling in patients with chronic heart failure: a pragmatic randomised clinical trial of feasibility and effectiveness

OBJECTIVES

The health benefits of high-intensity interval training in cardiac rehabilitation warrant further research. We compared the effectiveness of low-volume high-intensity interval training vs continuous aerobic exercise training in chronic heart failure.

DESIGN/SETTINGS

Unblinded, two arm parallel design with random assignment to exercise interventions in out-patient hospital rehabilitation gym.

METHODS

Patients with signs of chronic heart failure and ejection fraction < 45%, (mean age: 59.1 years (standard deviation (SD) 8.6); 3 women) completed 6 months of exercise using continuous aerobic exercise training (n = 9) or high-intensity interval training (n = 8). Cardiorespiratory fitness was determined during cycle ergometry using respiratory gas exchange analysis. Functional capacity was assessed via sit-to-stand and gait speed. Quality of life was assessed using the MOS Short-Form 36 and Minnesota living with heart failure questionnaires. Cardiac autonomic regulation was assessed using Heart Rate Variability.

RESULTS

Analysis of Covariance revealed significant time effects but no group × time interactions for exercise and functional capacity outcomes. Peak oxygen uptake (VO2peak) improved by a mean of 14.9% (SD 16.3%) from baseline and by 22% (SD 28.3) at ventilatory threshold in both groups. Sit-to-stand (11.9 (SD 11%)) and gait speed (16.0 (SD 19%)) improved similarly in both groups. No changes in quality of life or heart rate variability were noted. Training adaptations in high-intensity interval training were achieved despite a significantly reduced time commitment and total work volume compared to continuous aerobic exercise training.

CONCLUSION

Low-volume high-intensity interval training is a feasible and well tolerated training modality in cardiac rehabilitation settings, but is not more effective than continuous aerobic exercise training.

Exercise counselling practices for patients with chronic kidney disease in the UK: a renal multidisciplinary team perspective

BACKGROUND

Patients with chronic kidney disease (CKD) have elevated cardiovascular disease (CVD) risk. Physical activity (PA) is a strong and independent CVD risk factor, and despite the fact that current clinical practice guidelines recommend simultaneous treatment of multiple risk factors for optimum management of CKD, PA is rarely addressed by renal care teams. The aim of this observational cross-sectional survey was to document current exercise/PA practices across renal units in the UK, and capture views and experiences regarding the provision of PA/exercise options for patients with CKD.

METHODS

An 18-item online survey questionnaire regarding exercise counselling practice patterns was administered to 565 multidisciplinary renal care professionals.

RESULTS

142 individuals (25% response rate) completed the questionnaire. Overall, 42% of respondents discussed and encouraged PA, but only 18 and 11% facilitated implementation of PA for their patients. Nephrologists (p < 0.003) were more likely to prescribe or recommend PA compared to professionals with a nursing background and believed that specific renal rehabilitation services, including an active PA/exercise component, should be available to all patients (p < 0.01). The most commonly reported barriers for the development and implementation of PA/exercise options included lack of funding, time, and knowledgeable personnel, such as physiotherapists or other exercise professionals.

CONCLUSION

Beliefs and attitudes towards PA amongst members of the renal multidisciplinary team are encouraging. However there is a big gap between believing in the benefits of PA and promoting/implementing PA for patient benefit. This gap needs to be minimised by at least trying to address some of the reported barriers.

Effect of exercise training on estimated GFR, vascular health, and cardiorespiratory fitness in patients with CKD: a pilot randomized controlled trial

BACKGROUND

Exercise capacity, which is predictive of all-cause mortality and cardiovascular disease risk, is reduced significantly in patients with non-dialysis-dependent chronic kidney disease. This pilot study examined the effect of moderate-intensity exercise training on kidney function and indexes of cardiovascular risk in patients with progressive chronic kidney disease stages 3 to 4.

STUDY DESIGN

Single-blind, randomized, controlled, parallel trial.

SETTING & PARTICIPANTS

20 patients (aged 18-80 years; 17 men) randomly assigned to rehabilitation (n=10) or usual care (n=10). Participants were included if they were 18 years or older and had evidence of rate of decline in creatinine-based estimated glomerular filtration rate (eGFRcr)≥2.9mL/min/1.73m(2) per year for 12 months preintervention. Patients were excluded if they had unstable medical conditions or had recently started regular exercise.

INTERVENTION

The rehabilitation group received resistance and aerobic training (3 days per week) for a 12-month period. The usual care group received standard care.

OUTCOMES

Kidney function assessed by comparing mean rate of change in eGFRcr (mL/min/1.73m(2) per year) from a 12-month preintervention period against the 12-month intervention period. Pulse wave velocity (PWV), peak oxygen uptake (Vo2peak), and waist circumference assessed at 0, 6, and 12 months.

MEASUREMENTS

eGFR assessed using creatinine, cystatin C (eGFRcys), and a combination of both values (eGFRcr-cys).

RESULTS

18 participants (rehabilitation, 8; usual care, 10) completed the study. A significant mean difference in rate of change in eGFRcr (+7.8±3.0 [95% CI, 1.1-13.5] mL/min/1.73m(2) per year; P=0.02) was observed between the rehabilitation and usual care groups, with the rehabilitation group demonstrating a slower decline. No significant between-group mean differences existed in absolute eGFRcr, eGFRcr-cys, or eGFRcys at 12 months of study intervention. Significant between-group mean differences existed in PWV (-2.30 [95% CI, -3.02 to -1.59] m/s), waist circumference (-7.1±12.8 [95% CI, -12.4 to -3.2] cm), and Vo2peak (5.7 [95% CI, 1.34-10.10] mL/kg/min). Change in eGFRcr was correlated inversely with PWV (r=-0.5; P=0.04) at 12 months.

LIMITATIONS

Small sample size, inconsistency between primary and secondary measures of kidney function.

CONCLUSIONS

The effect of a 1-year exercise intervention on progression of kidney disease is inconclusive. A larger study with longer follow-up may be necessary.

Habitual functional electrical stimulation therapy improves gait kinematics and walking performance, but not patient-reported functional outcomes, of people with multiple sclerosis who present with foot-drop

BACKGROUND

People with Multiple Sclerosis (pwMS) often experience a disturbed gait function such as foot-drop. The objective of this pilot study was to investigate the medium term effects of using Functional Electrical Stimulation (FES) to treat foot-drop over a period 12 weeks on gait and patient reported outcomes of pwMS.

METHODS AND FINDINGS

Nine pwMS aged 35 to 64 (2 males, 7 females) were assessed on four occasions; four weeks before baseline, at baseline and after six weeks and twelve weeks of FES use. Joint kinematics and performance on the 10 meter and 2 minute walk tests (10WT, 2 minWT) were assessed with and without FES. Participants also completed the MS walking Scale (MSWS), MS impact scale (MSIS29), Fatigue Severity Score (FSS) and wore an activity monitor for seven days after each assessment. Compared to unassisted walking, FES resulted in statistically significant improvements in peak dorsiflexion in swing (p = 0.006), 10MWT (p = 0.006) and 2 minWT (p = 0.002). Effect sizes for the training effect, defined as the change from unassisted walking at baseline to that at 12 weeks, indicated improved ankle angle at initial contact (2.6°, 95% CI -1° to 4°, d = 0.78), and a decrease in perceived exertion over the 2 min walking tests (-1.2 points, 95% CI -5.7 to 3.4, d = -0.86). Five participants exceeded the Minimally Detectable Change (MDC) for a training effect on the 10mWT, but only two did so for the 2 minWT. No effects of the use of FES for 12 weeks were found for MSWS, MSIS29, FSS or step count.

CONCLUSION

Although FES to treat foot-drop appears to offer the potential for a medium term training effect on ankle kinematics and walking speed, this was not reflected in the patient reported outcomes. This observed lack of relationship between objective walking performance and patient reported outcomes warrants further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01977287.

Intra-dialytic exercise training: a pragmatic approach

This continuing education paper outlines the skills and knowledge required to plan, implement and evaluate a pragmatic approach to intra-dialytic exercise training.

AIM

The aim of this continuing education article is to enable the nephrology multi-disciplinary team (MDT) to plan, implement and evaluate the provision of intra-dialytic exercise training for patients receiving haemodialysis therapy.

LEARNING OUTCOMES

After reading this article the reader should be able to: Appreciate the level of evidence base for the clinical effectiveness of renal exercise rehabilitation and locate credible sources of research and educational information Understand and consider the need for appropriate evaluation and assessment outcomes as part of a renal rehabilitation plan Understand the components of exercise programming and prescription as part of an integrated renal rehabilitation plan Develop a sustainable longer term exercise and physical activity plan.

Experiences of functional electrical stimulation (FES) and ankle foot orthoses (AFOs) for foot-drop in people with multiple sclerosis

PURPOSE

A constructivist phenomenological study explored impacts of ankle foot orthoses (AFOs) or functional electrical stimulation (FES) on people with foot-drop from multiple sclerosis (MS).

METHOD

Focus groups following topic guides were analysed using interpretative phenomenological analysis, with researcher reflexivity, participant verification and peer checking of analysis. Participants with sustained use of the devices (under 2 y) were invited from two quantitative studies that (a) investigated immediate FES effects (n = 12) and (b) compared habitual use of AFO (n = 7) or FES (n = 6). Two focus groups addressed AFO (n = 4) and FES (n = 6) experiences.

RESULTS

Similar numbers of positive and negative aspects were described for AFO and FES. Both reduced fatigue, improved gait, reduced trips and falls, increased participation, and increased confidence; greater balance/stability was reported for AFOs, and increased walking distance, fitness and physical activity for FES. Barriers to both included avoiding reliance on devices and implications for shoes and clothing; a non-normal gait pattern was reported for AFO, and difficulties of application and limitations in the design of FES. However, participants felt the positives outweighed the negatives.

CONCLUSIONS

Participants felt benefits outweighed the drawbacks for AFO and FES; greater understanding of user preferences and satisfaction may increase likelihood of usage and efficacy. Implications for Rehabilitation Interventions to reduce the impacts of foot-drop in people with multiple sclerosis (MS) are important to optimise physical activity participation and participation in life; they include ankle foot orthoses (AFOs) and functional electrical stimulation (FES). Research is lacking regarding user satisfaction and perceived outcomes, therefore, two separate focus groups were conducted from a constructivist phenomenological perspective to explore the impacts of AFOs (n = 4) and FES (n = 6) on people with foot-drop from MS. Some similar positive aspects of AFO and FES use were described, including reduced fatigue, improved gait and fewer trips and falls, while common barriers included finding the device cumbersome, uncomfortable, and inconvenient, with some psychological barriers to their use. On balance, the impacts of the devices on improving activities and participation were more important for participants than practical barriers, highlighting the importance of combining understanding of individual experiences and preferences with clinical decision-making when prescribing a device to manage foot-drop.

Quantification of gait kinematics and walking ability of people with multiple sclerosis who are new users of functional electrical stimulation

OBJECTIVE

To assess whether the application of Functional Electrical Stimulation improves gait kinematics and walking ability in people with multiple sclerosis who experience foot drop.

DESIGN

Acute open labelled comparative observation trial.

PARTICIPANTS

Twelve people (3 females, 9 males, EDSS 2-4) with relapsing remitting multiple sclerosis (47.8 years (standard deviation 6.6)) who were new users of functional electrical stimulation.

METHODS

Gait kinematics were recorded using 3D gait analysis. Walking ability was assessed through the 10-m walk test and the 6-min walk test. All assessments were performed with and without the assistance of functional electrical stimulation. The effect of functional electrical stimulation was analysed using paired t-tests.

RESULTS

Ankle dorsiflexion at initial contact (p = 0.026), knee flexion at initial contact (p = 0.044) and peak knee flexion during swing (p = 0.011) were significantly greater whilst walking with Functional Electrical Stimulation. The increased peak dorsiflexion in swing of nearly 4 degrees during functional electrical stimulation assisted walking approached significance (p = 0.069). The 10-m walk time was significantly improved by functional electrical stimulation (p = 0.004) but the 6 min walk test was not.

CONCLUSION

The acute application of functional electrical stimulation resulted in an orthotic effect through a change in ankle and knee kinematics and increased walking speed over a short distance in people with multiple sclerosis who experience foot drop.

Exercise therapy in individuals with chronic kidney disease: a systematic review and synthesis of the research evidence

Chronic kidney disease (CKD) is becoming a serious health problem throughout the world and is one of the most potent known risk factors for cardiovascular disease (CVD) which is considered the leading cause of morbidity and mortality in this cohort of patients. Additional independent risk factors for poor health outcomes among many include diabetes, physical inactivity and physical dysfunction. Physical inactivity partly contributes to the accelerated deterioration of physical function in people in all stages of CKD, to levels that significantly impact on clinically and patient important outcomes such as morbidity, employment, quality of life (QoL) and ultimately survival. Ongoing research aims to determine the effectiveness and impact of exercise rehabilitation on reducing/managing the risk of CVD, alleviating physical function limitations, preventing disability and enhancing QoL. Current research also aims to elucidate the mechanisms via which exercise therapy may contribute to clinically relevant benefits.

The effects of tuning an ankle-foot orthosis footwear combination on kinematics and kinetics of the knee joint of an adult with hemiplegia

The effects of tuning the AFO footwear combination (AFOFC) for an adult with post-stroke hemiplegia were investigated. Gait analysis and tuning were carried out using a Vicon 3D motion analysis system and two force plates. Tuning of the AFOFC was accomplished by gradually modifying its design over a number of gait trials, to achieve optimal (i.e., as close as possible to normal, within the capability of the patient) knee kinematics and alignment of the Ground Reaction Force vector (GRF) relative to the knee joint. Heel wedges and a stiff rocker were used to tune mid-stance and terminal stance, respectively. Temporal-spatial parameters and selected kinetic and kinematic variables were compared between the non-tuned AFOFC, the tuned AFOFC immediately after tuning, and the tuned AFOFC after three months. There were several changes after three months compared to the non-tuned AFOFC, including improvement in stride length and a reduction in knee hyperextension. A subjective reduction in knee pain and improvement in function were also reported. The feasibility and the lack of objective evidence of tuning AFOFCs as a part of a clinical service need to be addressed in future research.

Patients receiving maintenance dialysis have more severe functionally significant skeletal muscle wasting than patients with dialysis-independent chronic kidney disease

BACKGROUND

Chronic renal replacement therapy patients exhibit reduction in skeletal muscle function as a result of a combination of metabolic effects and muscle fibre size reduction. The aim of this study was to compare muscle mass with function in patients with chronic kidney disease (CKD) at stages 4 and 5 on haemodialysis (HD) and peritoneal dialysis (PD), and investigate the associations of muscle wasting in a cross-sectional cohort.

METHODS

We studied 134 patients (60 HD, 28 PD and 46 CKD 4). The three groups were well matched for age, sex, diabetes and dialysis vintage. Cross-sectional area (CSA) of muscle and fat was measured from a standardized multi-slice CT scan of a 6 cm long section of thigh. CSA of soft tissue was taken from appropriate fat and muscle densities. Functional assessment was by the sit-to-stand 60 test, assessing both the number of sit-to-stands possible under controlled conditions in 60 s (STS 60), and the time taken to perform five sit-to-stand movements (STS 5). Data were collected on a wide range of potential determinants of muscle CSA.

RESULTS

There were no significant differences in haemoglobin between males or females or between any of the groups studied. Serum phosphate and calcium-phosphate product were higher in HD patients as compared to CKD4 patients, but there were no differences in these variables when comparing PD patients with either CKD4 or HD patients. Muscle CSA correlated well with objective functional assessments in males (STS 60 R = 0.52, P<0.0001) and females (R = 0.41, P = 0.004), and STS performance was reduced in dialysed patients as compared with CKD 4. Univariate analysis demonstrated that muscle CSA was associated with serum albumin concentration (R = 0.49, P<0.0001), age (R = -0.35, P = 0.005) and C-reactive protein (R = -0.34, P = 0.004). Creatinine clearance, dialysis adequacy, dialysis vintage and time-averaged serum bicarbonate, calcium and phosphate concentrations were not correlated with muscle CSA.

CONCLUSION

In conclusion, patients with dialysis-treated CKD 5 exhibited more functionally significant muscle wasting than patients with CKD 4. This may be amenable to modification with targeted exercise or amelioration of factors associated with observed differences in muscle mass.

Skeletal muscle morphology and capillarization of renal failure patients receiving different dialysis therapies

The morphology of gastrocnemius muscles was examined in RFPs (renal failure patients) being treated using HD (haemodialysis) and CAPD (continuous ambulatory peritoneal dialysis). RFPs (n=24) volunteered to participate in the present study. Twelve RFPs (five women and seven men; mean age, 55 years) were undergoing CAPD treatment and 12 RFPs (two women and ten men; mean age, 62 years) were undergoing HD treatment. Muscle biopsies from gastrocnemius muscles were found not to differ (P>0.05) in fibre type distribution, MyHC (myosin heavy chain) expression or fibre CSA (cross-sectional area) between the two groups. There were, however, significant differences (P<0.05) in CC/F (capillary contact/fibre), C/F (capillary to fibre ratio) and cytochrome c oxidase activity. The HD group had 33% more CC/F, with a 19% higher C/F and 33% greater cytochrome c activity in glycolytic fibres (II) than the CAPD group. There were no apparent differences in age, gender, co-morbidity, self-reported physical activity or physical functioning between the two groups, which could account for the difference in muscle capillarity between the groups. The HD patients were, however, administered heparin as a routine part of the dialysis therapy. The possibility is discussed that heparin in combination with mild anaemia and acidosis may have augmented angiogenesis in the HD patients.

Nutritional status, functional capacity and exercise rehabilitation in end-stage renal disease

A significant percentage of patients with end-stage renal disease are malnourished and/or muscle wasted. Uremia is associated with decreased protein synthesis and increased protein degradation. Fortunately, nutritional status has been shown to be a modifiable risk factor in the dialysis population. It has long been proposed that exercise could positively alter the protein synthesis-degradation balance. Resistance training had been considered as the only form of exercise likely to induce anabolism in renal failure patients. However, a small, but growing, body of evidence indicates that for some dialysis patients, favourable improvements in muscle atrophy and fibre hypertrophy can be achieved via predominantly aerobic exercise training. Moreover, some studies tentatively suggest that nutritional status, as measured by SGA, can also be modestly improved by modes and patterns of exercise training that have been shown to also increase muscle fibre cross-sectional area and improve functional capacity. Functional capacity tests can augment the information content of basic nutritional status assessments of dialysis patients and as such are recommended for routine inclusion as a feature of all nutritional status assessments.

Atrophy of non-locomotor muscle in patients with end-stage renal failure

BACKGROUND

All previous histological studies of skeletal muscles of patients with renal failure have used locomotor muscle biopsies. It is thus unclear to what degree the observed abnormalities are due to the uraemic state and how much is due to disuse. The present study was undertaken to attempt to investigate this question by examining a non-locomotor muscle (rectus abdominis) in patients with end-stage renal failure.

METHODS

Biopsies from rectus abdominis were obtained from 22 renal failure patients (RFPs) undergoing surgical Tenchkoff catheter implantation for peritoneal dialysis and 20 control subjects undergoing elective abdominal surgery. Histochemical staining of frozen sections and morphometric analysis was used to estimate the proportion of each fibre type, muscle fibre area and capillary density. Myosin heavy chain composition was examined by SDS-PAGE.

RESULTS

There were no differences in fibre type distribution between RFPs and controls. All RFPs showed fibre atrophy [mean cross-sectional area (CSA) 3300 +/- 1100 microm2, compared to 4100 +/- 1100 microm2 in controls (P < 0.05)]. All fibre types were smaller in mean CSA in RFPs than in controls (15, 26 and 28% for types I, IIa and IIx, respectively). These differences could not be accounted for by differences in age, gender or cardiovascular or diabetic comorbidity. Muscle fibre capillarization, expressed as capillaries per fibre or capillary contacts per fibre, was significantly less in RFPs.

CONCLUSIONS

Since a non-locomotor muscle was examined, the effects of disuse as a cause of atrophy have been minimized. It is likely, therefore, that the decreased muscle fibre CSA and capillary density of RFPs compared to controls were due predominantly to uraemia itself.

Changes in muscle morphology in dialysis patients after 6 months of aerobic exercise training

BACKGROUND

In the present study we investigated the effect of a 6-month aerobic exercise programme on the morphology of the gastrocnemius muscle of end-stage renal disease (ESRD) patients.

METHODS

Twenty-four ESRD patients volunteered to participate in the training programme and underwent muscle biopsy before training. Eighteen patients completed the training programme of whom nine agreed to a post-training biopsy (one woman and eight men, mean age 56 +/- 15 years). Data are presented for the nine subjects who were biopsied before (PRE) and after training (POST) and separately for the 15 subjects for whom we only have a biopsy before training (cross-sectional group).

RESULTS

There were no significant differences (P > 0.05) in fibre type distribution or myosin heavy chain (MyHC) expression between the cross-sectional and PRE/POST groups. The mean cross-section fibre area after training (POST) increased by 46% compared with the PRE training status (P < 0.01). The proportion of atrophic fibres decreased significantly after training in type I, IIa and IIx fibre populations (from 51 to 15%, 58 to 21% and 62 to 32%, respectively). Significant differences were also found in capillary contact per fibre (CC/F), with the muscle having 24% (P < 0.05) more CC/F compared with the PRE training status. No significant differences in cytochrome c oxidase concentration were found between the groups.

CONCLUSIONS

In conclusion, exercise appeared to be beneficial in renal rehabilitation by correcting the fibre atrophy, increasing the cross-section fibre area and improving the capillarization in the skeletal muscle of renal failure patients.

An alternative histochemical method to simultaneously demonstrate muscle nuclei and muscle fibre type

We present a modified histochemical method to examine, simultaneously, nuclei and fibre type in human skeletal muscle. The new procedure (Haem-ATPase) is based on two previously used histochemical protocols. Biopsies were obtained from the rectus abdominis muscle of patients undergoing elective abdominal surgery. Fibre type composition, cross-sectional area (CSA) and nuclei to fibre ratio (N:F) were determined from frozen sections of each biopsy. To test the validity of the new method, serial sections of each biopsy were stained separately using the standard and modified methods. No differences were found in fibre type distribution, mean-weighted CSA and N:F when comparing the modified method with the standard methods. The Haem-ATPase method was found to shrink fibre size by at least 3% ( P>0.05) compared with the established myosin acid labile method. We propose that this modified technique is suitable for initial examination of both the nuclei and fibre type in the same frozen sections of human skeletal muscle.

Reliability of indices of neuromuscular leg performance in end-stage renal failure

The purpose of this study was to examine the day-to-day reproducibility and single measurement reliability of peak force, time to half peak force and rate of force development indices of knee extension neuromuscular performance in patients with end-stage renal failure. Eleven self-selected patients (6 men, 5 women) receiving maintenance dialysis (dialysis history 67 +/- 42.8 month) completed 3 inter-day assessment sessions. Each comprised a standardized warm-up and 3 intermittent static maximal voluntary actions of the knee extensors of the preferred limb (45 degrees knee flexion angle [0 degrees = full knee extension]) using a specially-constructed dynamometer. Repeated measures ANOVA of coefficient of variation scores revealed significant differences between indices in their reproducibility across day-to-day trials. Post-hoc comparisons of group mean scores suggested that peak force (6.6 +/- 3.0%) offers significantly greater measurement reproducibility than time to half peak force (16.8 +/- 9.5%) or rate of force development (20.3 +/- 12.1%). Intraclass correlation coefficients and standard error of measurement scores showed that single-trial assessments of peak force, time to half peak force and rate of force development would demonstrate limited precision and capability to discriminate subtle intra-subject or inter-subject changes in neuromuscular performance.

Assessing the efficacy of exercise training in patients with chronic disease

PURPOSE

The purpose of this study was to evaluate the meaningfulness of exercise training responses in patients with end stage renal disease (ESRD).

METHODS

Eighteen ESRD patients [(mean +/- SD); 54.3 +/- 17.1 yr] completed a training regime progressing to accumulate 40 min of stationary cycling, three times per week for 6 months. .VO(2peak) determined via incremental cycle ergometer protocol, and .VO(2) kinetics determined from a transition from unloaded pedalling to an exercise intensity corresponding to 90% of VT, were assessed at baseline and at 3 and 6 months of training.

RESULTS

Repeated measures analysis of variance revealed significant changes (P < 0.05) on the time factor for .VO(2peak), VO(2)-V(T), and .VO(2) kinetics. Post hoc analysis revealed that .VO(2peak) and .VO(2) kinetics significantly (P < 0.05) improved at 3 months of training with no further improvements thereafter. Analysis of individual subject response data revealed that after 3 months of training, 61% of the patients improved .VO(2peak) by greater than the standard error of measurement (SEM = 0.07 L.min(-1)). At 6 months of training, approximately 89% of the patients improved by more than the SEM .VO(2) kinetics improved by more than the SEM (12.3 s) at 3 months of training in approximately 55% of the patients, with no increase in the number of patients exhibiting faster time constants after 6 months of training.

CONCLUSION

Although conventional statistical analyses indicate that exercise training favorably alters .VO(2peak) and oxygen uptake kinetics of patients with ESRD, it is apparent that considerable interindividual variability exists in the response to training. Consideration of the SEM data underscores the heterogeneity of adaptive response in this patient group and may be valuable in assessing the efficacy of therapeutic exercise rehabilitation.

Effects of exercise training on aerobic and functional capacity of end-stage renal disease patients

The aim was to assess the effects of exercise training on aerobic and fuctional capacity of patients with end-stage renal disease (ESRD). Patients completed an incremental exercise test on a cycle ergometer to determine VO2 peak and VO2 at ventilatory threshold (VT; V-slope). On a separate day they performed two constant load exercise tests on a cycle ergometer at 90% of VT and at a workload of 33 W, to determine VO2 kinetics. Functional capacity was assessed using measurements of sit-to-stands (STS-5, STS-60) and a walk test. Dialysis patients were randomly allocated to an exercise (ET: n = 18, age = 57.3 years) or control (C: n = 15, age = 50.5 - 5 years) group. The ET group participated in an exercise training programme involving cycling for 3 months. Repeated measures ANOVA revealed significant time by group interactions (P < 0.05) following training for VO2 peak (ET: 17 +/- 6.1 versus 19.9 +/- 6-3, C: 19.5 +/- 4.7 versus 188 +/- 4.9 ml kg min(-1)) and VO2-VT (ET: 10.7 +/- 3.5 versus 11.8 +/- 3.3, C:12.9 +/- 3.2 versus 119 +/- 3.5 ml kg min(-10). VO2 kinetics remained unchanged in both groups at 90% -VT, but a trend (P = 0.059) towards faster kinetics at the 33 W was observed (ET: 49.6 +/- 19.5 versus 37.8 +/- 12.7, C: 42.8 +/- 13 versus 49.4 +/- 20.2 s). Significant time by group interactions (P < 0.05) were also observed for STS-5 (ET: 14.7 +/- 6.2 versus 11.0 +/- 3.3, C: 12.8 +/- 4.4 versus 12.7 +/- 4.8 s) and STS-60 measurements (ET: 21.2 + 7.2 versus 26.9 +/- 6.2, C: 23.7 +/- 6.8 versus 24.1 +/- 7.2). Three months of exercise rehabilitation significantly improves peak exercise capacity of patients with ESRD. Measurements of VO2 kinetics and functional capacity suggest that longer time might be needed to induce peripheral adaptations.

Low-volume exercise rehabilitation improves functional capacity and self-reported functional status of dialysis patients

OBJECTIVE

The purpose of this study was to examine the effects of a program of low-volume exercise rehabilitation on the functional capacity and self-reported functional status of nonanemic dialysis patients.

DESIGN

This was a controlled study in a clinical setting with a repeated measures design. Functional capacity and functional status were assessed before and after 12 wk of exercise rehabilitation or 12 wk of normal activity for two groups of dialysis patients.

RESULTS

Mixed-model repeated measures analysis of variance revealed significant group by time interactions characterized by improvements for the exercise rehabilitation group alone in total walk, stair-climb, and stair-descent times of 15+/-5.8%, 22+/-11%, and 18+/-12% respectively. Self-reported walking speed, walking impairment-leg weakness, and walking impairment-shortness of breath were also observed to improve significantly for the exercise rehabilitation group alone by 15+/-13%, 25+/-11%, and 28+/-16%, respectively.

CONCLUSION

Low-volume exercise rehabilitation can improve activity of daily living-related functional capacity and self-reported functional status of nonanemic dialysis patients.

Reproducibility of exercise tolerance in patients with end-stage renal disease

OBJECTIVE

To determine the interday reproducibility of peak and submaximal exercise tolerance of patients with end-stage renal disease (ESRD).

DESIGN

Repeated measures.

SETTING

Day-patient rehabilitation center.

PARTICIPANTS

Twelve consecutively presenting, self-selected patients with ESRD.

INTERVENTIONS

All patients performed peak exercise tolerance assessments on a cycle ergometer up to the point of volitional fatigue, with a 1-week interval between the 2 tests.

MAIN OUTCOME MEASURES

Cardiopulmonary, hemodynamic, and physical performance parameters were assessed at peak exercise and at the lactate threshold. Standard error of measurement, percentage coefficient of variation (CV%), intraclass correlation coefficient (ICC), and limits of agreement (LOA) were calculated to determine the reproducibility of all variables.

RESULTS

CV% (range, 5%-7%) and ICCs (range, .94 - .98) for oxygen uptake and heart rate at peak exercise and lactate threshold indicated highly acceptable levels of group mean reproducibility. LOA analysis revealed satisfactory levels of reproducibility for individual patients.

CONCLUSION

Taken together, these reproducibility data may be applied to clinical work, requiring the quantification of changes in the exercise tolerance of patients with ESRD after short-term interventions (eg, exercise training, therapeutic use of recombinant erythropoietin).

Reproducibility of blood lactate-anchored ratings of perceived exertion

This study investigated the reproducibility of blood lactate-anchored ratings of perceived exertion (RPE) in seven women of average, and seven of above average cardiorespiratory fitness, [moderate and high maximal oxygen uptake (Mod VO2max and High VO2max, respectively)]. The subjects completed a series of four exercise tests, comprising a VO2max assessment and three O-grade, velocity-incremental, treadmill-running RPE estimation trials. The results revealed no significant between-group differences in RPE at the blood lactate concentration threshold (LT), and at reference levels of 2, 2.5 or 4 mmol x l(-1) (RPELT, RPE2, RPE2.5 and RPE4, respectively). The RPELT, RPE2, RPE2.5 and RPE4 were characterised by intra-class correlation coefficients of 0.97, 0.97, 0.97, 0.72 and 0.83, 0.96, 0.96, 0.90, in the High VO2max and Mod VO2max groups, respectively. The SEM% (95% confidence limits computed as a percentage of the group mean score) largely mirrored the trend in reliability with the highest values observed for RPELT in the Mod VO2max group and RPE4 in the High VO2max group. The Spearman-Brown prediction equation indicated that fixed blood lactate concentrations of 2, 2.5 and 4 mmol x l(-1) offer acceptable practical utility as potential perceptual anchor points for both groups, requiring one trial only to achieve a measurement error of less than +/- 6%.

Development of a walking test for the assessment of functional capacity in non-anaemic maintenance dialysis patients

BACKGROUND

Walk tests may be useful adjuncts or even alternatives to the assessment of peak oxygen uptake (VO2 peak) in patients with low functional capacity. Walk tests are easy to administer, appear to be well tolerated by patients and may represent a more meaningful measure for a patient group as they assess capability as well as fitness. However, the use of walk tests for the assessment of functional capacity in maintenance dialysis patients has received scant attention. The aim of this study was to assess the validity of a walking-stair-climbing test to predict VO2 peak in non-anaemic maintenance dialysis patients.

METHODS

In the validation phase of the study, 14 subjects completed a cycle ergometer-graded exercise test (GXT) for the determination of VO2 peak and a walking-stair-climbing task (WALK), each separated by a period of 7 days. Three weeks later, 18 subjects completed two WALK tests, each separated by a period of at least 48 h, to facilitate reliability estimation. Estimates of differentiated and undifferentiated ratings of perceived exertion (RPE) were obtained during and immediately consequent to all exercise tests.

RESULTS

VO2 peak (ml kg min) was significantly correlated with total WALK time (s) (r = -0.83; P < 0.001). VO2 peak (ml/kg/min) could be predicted from total WALK time with a standard error of prediction of 11%. Reliability assessment revealed no significant differences for any aspect of the WALK test performance, with intraclass correlation coefficients ranging from r = 0.71 (RPElegs) to 0.96 (total WALK time).

CONCLUSION

These results indicate that the WALK test is a valid, reliable and potentially useful method by which to assess the functional capacity of non-anaemic maintenance dialysis patients.

Prolonged intermittent high intensity exercise impairs neuromuscular performance of the knee flexors

This study investigated the effect of prolonged intermittent high intensity exercise upon the isokinetic leg strength and electromechanical delay of the knee flexors. Seven male collegiate soccer players were exposed to: (i) a prolonged intermittent high intensity exercise task (PIHIET) which required subjects to complete a single-leg pedalling task, with the preferred limb, (75 rpm for all constant-load portions of the task) consisting of 48 x 1.8 minute cycles of exercise, and (ii) a control task consisting of no exercise. Pre-, mid- and post-PIHIET gravity corrected indices of knee flexion angle-specific torque (0.44 rad knee flexion (AST); 0 rad=full knee extension; [1.05 rad x s(-1)]) were made for both intervention and control limbs. Electromechanical delay (EMD) of the m. biceps femoris during supine knee flexion movements was evaluated in the preferred leg on both intervention and control days. Repeated measures ANOVAs revealed significant condition (intervention; control) by time (pre; mid; post) interactions for both knee flexor AST (F[2,12]=4.8; p < 0.03) and EMD (F[2,12]=4.1; p < 0.05). AST was observed to decrease by 16% and EMD increase by 30% pre to post intervention. These observations suggest an impairment of neuromuscular control and the ability to maintain force generation in the knee flexors, near the extremes of the range of motion during prolonged intermittent high-intensity exercise activities. Changes of this magnitude may pose a threat to the integrity of the knee joint.

Influence of acute endurance activity on leg neuromuscular and musculoskeletal performance

PURPOSE

The purpose of this study was to investigate the effect of endurance activities designed to simulate the physiological demands of soccer match-play and training, on leg strength, electromechanical delay, and knee laxity.

METHODS

Eight recreational soccer players completed four exercise trials in random order: 1) a prolonged intermittent high intensity shuttle run (PHISR) which required subjects to complete a total distance of 9600 m in a form simulating the pattern of physical activity in soccer match-play (activity mode; rest-to-work intervals; approximately 90 min duration), 2) a shuttle-run (SR), (3) a treadmill run (TR) which required subjects to complete an equivalent distance at a running speed corresponding to 70% VO2max, and 4) a control condition consisting of no exercise.

RESULTS

Results from repeated measures ANOVA revealed significant condition (PHISR; SR; TR; control) by time (pre; mid; post) interactions for peak torque (PT: knee extension and flexion: 1.05 rad.s-1), EMD and anterior tibio-femoral displacement (TFD) (P < 0.05). Impairment to indices of knee joint performance was observed in PHISR, SR, and TR trials. The greatest decrement occurred in PHISR and SR trials (up to 44%). Knee extensor and flexor strength performance near to full knee extension (0.44 rad knee flexion) was not changed following the functionally-relevant endurance activities.

CONCLUSIONS

Even though strength performance near to full knee extension was preserved following acute endurance activities, the risk of ligamentous injury may be increased by concomitant impairment to EMD and anterior TFD.