Relation Between Muscular Strength and Cardiorespiratory Fitness in People With Thoracic-Level Paraplegia

Cardiorespiratory and aerobic demands of squat exercise

Squatting, a traditional resistance exercise classified as strength training, relies on anaerobic pathways, but its aerobic aspects remain unclear. We examined heart rate and oxygen demand during squats, exploring variations across different strength statuses. It fills gaps in understanding the cardiorespiratory effects of squatting, especially during multiple sets. Twenty-two young healthy resistance trained men (age: 28 ± 4 years) participated. Maximal oxygen consumption (V̇O2max) and 1 repetition maximum (RM) of squat were measured. Participants performed 5 sets of squat exercises at 65% of 1RM for 10 repetitions with 3-min rest intervals. Heart rate and pulmonary gas exchange were measured during the squat exercise. Participants were divided into high strength (HS; upper 50%) and low strength (LS; lower 50%) groups based on a median split of their 1 RM squat values (normalized to their body weight). During 5 sets of squat exercise, oxygen consumption (V̇O2) increased up to 47.8 ± 8.9 ml/kg/min, corresponding to 100.6% of predetermined V̇O2max. The HS group achieved a greater highest point of V̇O2 in relation to V̇O2max than the LS group (108.0 vs. 93.7%). During the exercise intervals, V̇O2 exceeded V̇CO2, while during the rest intervals, V̇CO2 surpassed V̇O2. Our findings suggest that the oxygen demand during squatting is notably substantial, which may vary according to the training status.

Strength training as a non-pharmacological alternative to improve body composition, and quality of life in people with spinal cord injury: A systematic review

INTRODUCTION

Spinal cord injuries (SCI) have physiological, emotional, and economic consequences in the lives of affected people. Resistance training (RT) is efficient in improving several physiological factors, quality of life, and body composition. Due to the scarce literature on the analysis of isolated RT, the objective of this systematic review is to evaluate the effects of RT without the association of other techniques, in aspects related to the quality of life and body composition of people with SCI.

EVIDENCE ACQUISITION

The research was carried out in databases such as Pubmed, Cochrane, and Web of Science using the terms ("Spinal cord injury") AND (("Resistance Training") OR ("Strength training")). Given the lack of evidence on the subject, no deadline was set for the study to be eligible for analysis.

EVIDENCE SYNTHESIS

The search for the articles was carried out in November of 2023 and returned 470 results, of which 315 remained after the elimination of duplicates, with 281 being excluded after title analysis. A total of 34 abstracts were analyzed and 29 studies were excluded, leaving 5 complete articles for thorough analysis.

CONCLUSIONS

After analyzing the main results, we concluded that RT promotes significant improvements in body composition, pain, stress and depression symptoms, increased functionality, physical awareness, and quality of life.

Post-processing Peak Oxygen Uptake Data Obtained During Cardiopulmonary Exercise Testing in Individuals With Spinal Cord Injury: A Scoping Review and Analysis of Different Post-processing Strategies

OBJECTIVES

To review the evidence regarding the most common practices adopted with cardiopulmonary exercise testing (CPET) in individuals with spinal cord injury (SCI), with the following specific aims to (1) determine the most common averaging strategies of peak oxygen uptake (V̇o2peak), (2) review the endpoint criteria adopted to determine a valid V̇o2peak, and (3) investigate the effect of averaging strategies on V̇o2peak values in a convenience sample of individuals with SCI (between the fourth cervical and sixth thoracic spinal segments).

DATA SOURCES

Searches for this scoping review were conducted in MEDLINE (PubMed), EMBASE, and Web Science.

STUDY SELECTION

Studies were included if (1) were original research on humans published in English, (2) recruited adults with traumatic and non-traumatic SCI, and (3) V̇o2peak reported and measured directly during CPET to volitional exhaustion. Full-text review identified studies published before April 2021 for inclusion.

DATA EXTRACTION

Extracted data included authors name, journal name, publication year, participant characteristics, and comprehensive information relevant to CPET.

DATA SYNTHESIS

We extracted data from a total of 197 studies involving 4860 participants. We found that more than 50% of studies adopted a 30-s averaging strategy. A wide range of endpoint criteria were used to confirm the attainment of maximal effort. In the convenience sample of individuals with SCI (n=30), the mean V̇o2peak decreased as epoch (ie, time) lengths increased. Reported V̇o2peak values differed significantly (P<.001) between averaging strategies, with epoch length explaining 56% of the variability.

CONCLUSIONS

The adoption of accepted and standardized methods for processing and analyzing CPET data are needed to ensure high-quality, reproducible research, and inform population-specific normative values for individuals with SCI.

Handgrip Strength Cutoff Points for Functional Independence and Wheelchair Ability in Men With Spinal Cord Injury

Objectives

To determine optimal handgrip strength (HGS) cutoff points for greater functional independence and wheelchair skills in men with spinal cord injury (SCI), and to establish predictive equations for functional independence and wheelchair ability in men with SCI, based on demographic characteristics, HGS, and functionality.

Methods

In this cross-sectional study conducted at a rehabilitation hospital, 54 men with SCI were recruited and stratified into high and low paraplegia groups. All participants performed a maximum HGS test to determine cutoff points for the Spinal Cord Independence Measure (SCIM-III) and Adapted Manual Wheelchair Circuit (AMWC). The primary outcomes were the SCIM-III, AMWC, and HGS. Demographic characteristics obtained from participants' electronic medical records were the secondary outcomes, used as predictor variables of functional independence.

Results

The SCIM-III scale, performance score, and 3-minute overground wheeling test presented significant regression equations (R = 0.45, R = 0.69, and R = 0.72). The HGS showed a cutoff point of 102.5 kilogram force (kgf) to achieve a score of 70 on the SCIM-III and a 3-minute overground wheeling distance of 270 m. The HGS cutoff point to obtain a performance score of 23.7 seconds was 93.0 kgf.

Conclusion

The HGS was a significant predictor for the SCIM-III score, AMWC performance score, and 3-minute overground wheeling test. Three significant predictive equations were established based on HGS. The cutoff points could be adopted as parameters for optimal functional independence and wheelchair skills.

Peak Torque Prediction Using Handgrip and Strength Predictors in Men and Women With Motor Complete Spinal Cord Injury

OBJECTIVES

To establish predictive equations for peak torque of muscle groups with totally and partially preserved innervation in individuals with motor complete spinal cord injury (SCI), based on hand dynamometry and strength predictor variables.

METHODS

The cross-sectional study conducted at a rehabilitation hospital consecutively recruited 108 men and women with SCI. All participants performed maximum peak torque tests for shoulder abduction/adduction (isokinetic), trunk flexion/extension (isometric), and handgrip strength testing (hand dynamometer) to establish predictive peak torque equations. The primary outcomes were peak torque variables. Handgrip strength, age, injury level, time since injury, age at injury, body mass, height, body mass index, and physical activity level were the secondary outcomes used as strength predictor variables.

RESULTS

Handgrip strength was a predictor variable for shoulder abduction/adduction peak torque. The best predictive models for shoulder abduction/adduction peak torque exhibited R 2 = 0.57 and R 2 = 0.60, respectively (p ≤ .05). Injury level showed the highest significant predictive capacity for trunk flexion/extension peak torque models (R 2 = 0.38 and R 2 = 0.29; p ≤ .05).

CONCLUSION

Shoulder abduction/adduction peak torque predictive equations may be an alternative for use in an accessible strength tool (hand dynamometry) to evaluate training and rehabilitation programs. Trunk flexion/extension peak torque equations exhibited moderate correlations and high standard error of the estimates and should be used with caution.

Effects of 7-week Resistance Training on Handcycle Performance in Able-bodied Males

The effect of an upper body resistance training program on maximal and submaximal handcycling performance in able-bodied males was explored. Eighteen able-bodied men were randomly assigned to a training group (TG: n=10) and a control group (CG: n=8). TG received 7 weeks of upper body resistance training (60% of 1 repetition maximum (1RM), 3×10 repetitions, 6 exercise stations, 2 times per week). CG received no training. Peak values for oxygen uptake (V˙O_2peak), power output (PO_peak), heart rate (HR_peak), minute ventilation (V˙O_Epeak) and respiratory exchange ratio (RER_peak), submaximal values (HR, V˙O₂, RER, PO, and gross mechanical efficiency (GE)), and time to exhaustion (TTE) were determined in an incremental test pre- and post-training. Maximal isokinetic arm strength and 1RM tests were conducted. Ratings of perceived exertion (RPE) were assessed. A two-way repeated measures ANOVA and post-hoc comparisons were performed to examine the effect of time, group and its interaction (p<0.05). TG improved on PO_peak (8.55%), TTE (10.73%), and 1RM (12.28-38.98%). RPE at the same stage during pre- and post-test was lower during the post-test (8.17%). Despite no improvements in V˙O_2peak, training improved PO_peak, muscular strength, and TTE. Upper body resistance training has the potential to improve handcycling performance.

The Torque Referenced to a Perceived Exertion Level Is Affected by the Type of Movement in Men With Spinal Cord Injury

Objectives

To compare a standardized submaximal intensity (based on the rate of perceived exertion [RPE]) with the percentage of the average and peak torque during a familiarization session in individuals with different spinal cord injury (SCI) levels in gravity-resisted and gravity-assisted movements.

Methods

This was a cross-sectional study at a rehabilitation hospital. Thirty-six individuals stratified in tetraplegia (TP), high paraplegia (HP), and low paraplegia (LP) groups and 12 matched control participants (CG) were enrolled in the study. Participants performed a maximum strength test using isokinetic dynamometry. The familiarization consisted of 10 submaximal repetitions with a level 2 (i.e., 20% of the maximum score) in the Resistance Exercise Scale (OMNI-RES). Fisher's exact test compared the percentages of the average torque (%AT_Fam) and peak torque (%PT_Fam) of the familiarization (based on the peak torque during the maximum strength tests) to the %AT_Fam and %PT_Fam attained with 20% of RPE. The coefficient of variation (CV) was calculated to assess the torque dispersion during each familiarization set.

Results

The %AT_Fam was lower for gravity-assisted compared to gravity-resisted movements for HP, LP, and CG (p ≤ .05). The CV was significantly lower in gravity-resisted movements during familiarization for TP, LP, and CG.

Conclusion

Different RPE levels should be adopted for gravity-resisted or gravity-assisted upper limb exercises to maintain the same relative intensity during a familiarization session.

Differences of Relative and Absolute Strength of Individuals With Spinal Cord Injury From Able-Bodied Subjects: A Discriminant Analysis

CONTEXT

Strength training is one of the most common interventions employed to increase functional independence during rehabilitation of individuals with spinal cord injury (SCI). However, in the literature, different results have been reported in terms of strength modifications after a SCI compared with a control group (CG).

OBJECTIVE

This study aimed to verify whether discriminant analysis using relative and absolute strength is able to discriminate individuals with different levels of SCI from a CG and to compare strength values of men with different levels of SCI with a CG.

DESIGN

Cross-sectional study.

SETTING

Rehabilitation hospital setting.

PARTICIPANTS

A total of 36 individuals with SCI stratified in tetraplegia (TP; C6-C8), high paraplegia (HP; T1-T6), and low paraplegia (LP; T7-L2), and 12 matched control subjects were enrolled in the study.

MAIN OUTCOME MEASURES

The subjects performed a maximum strength test of elbow extension/flexion and also shoulder abduction/adduction and flexion/extension in an isokinetic dynamometer. Discriminant analysis was carried out to identify which strength variables would be able to discriminate the TP, HP, or LP groups from the CG. A 1-way analysis of variance was performed to compare peak torque and agonist/antagonist ratio means.

RESULTS

Shoulder adduction, followed by elbow extension peak torque, was the best variable for discriminating the TP group from the CG (function coefficients: -0.056 and 0.051, respectively, Wilks Λ = 0.41, P ≤ .05). There were no significant differences between the HP group, LP group, and CG.

CONCLUSIONS

The strength similarity of the paraplegic groups and the CG should not be extrapolated for activities of daily living or sports. The TP group demonstrated lower peak torque for all movements than the CG.

The influence of operator and wheelchair factors on wheelchair propulsion effort

Purpose: The goal of this study was to evaluate the relative influence of operator and wheelchair factors on propulsion effort during over-ground wheelchair manoeuvres.Method: This observational study included 23 full-time manual wheelchair users and 13 able-bodied subjects. The operator factors included shoulder position, aerobic capacity and propulsion strength. The wheelchair factors included system mass, weight distribution, and frictional loss in straight and turning trajectories. The performance of over-ground manoeuvres was defined as the propulsion effort measured by VO₂ as operators propelled along a modified figure-8 course on tile and carpet surfaces.Results: According to our regression model, shoulder position was the only significant contributor within operator factors, whereas weight distribution was the only significant contributor within wheelchair factors in influencing propulsion efforts. When combining operator and mechanical factors in the regression model, weight distribution became the only significant contributor to influence propulsion effort.Conclusion: Weight distribution and shoulder position had a significant influence on propulsion effort. These variables are related to the operator's relationship to the drive wheels. However, system mass and muscle strength had the least influence on wheelchair manoeuvres. Our finding can help clinicians to improve wheelchair configurations and manufacturers to improve wheelchair design by understanding the importance of shoulder position and weight distribution.Implication for rehabilitationStudying wheelchair manoeuvers by considering both wheelchair and operator factors might provide a unique insight to address the complex interactions among wheelchair designs and users.Propulsion effort decreases as percentage weight is increased on the drive wheels and the shoulder becomes more aligned with the axle position, which highlights the need to optimize wheelchair axle position.Wheelchair configuration, as represented by weight distribution, had a more significant influence on everyday manoeuvre than wheelchair mass does.It is essential for wheelchair users to choose a wheelchair that can match their daily needs and anthropometric measurements for saving propulsion efforts.

Predictive factors of peak aerobic capacity using simple measurements of anthropometry and musculoskeletal fitness in paraplegic men

BACKGROUND

Protocols for evaluating cardiovascular fitness for wheelchair-dependent persons are still scarcely accessible due to the requirements such as specialized equipment and expertise in community or public healthcare settings. This study aimed to assess the potential of secondary utilization of musculoskeletal fitness components for estimating peak oxygen uptake (VO2peak) in paraplegic men.

METHODS

Thirty-three paraplegic men (T1-L3) aged 23-63 years underwent anthropometry (height, weight and calculated body mass index and body surface area) and upper-body musculoskeletal fitness tests (back-scratch, arm-curls and handgrip strength tests) and performed a graded exercise test with an arm-crank ergometer on two non-consecutive days. To determine the relationship between VO2peak and various kinanthropometric parameters and derive a regression model that predicts the VO2peak, uni- and multivariate analyses were conducted, respectively.

RESULTS

Maximal numbers of arm curls on either arm (r=0.486, P=0.004) and the back-scratch distance (r=0.426, P=0.013) were moderately correlated with VO2peak. Moreover, among the indices of handgrip strength, average handgrip strength of both hands divided by the body surface area showed a strong correlation coefficient with VO2peak (r=0.674, P<0.001). Multivariate linear regression analysis indicated that muscular endurance and strength were the main predictors for estimating VO2peak. Considering shoulder flexibility, age, and anthropometric variables, the regression model showed the highest adjusted R2 of 0.811 and lowest standard error of estimate of 3.54 mL·kg-1·min-1 (P<0.001). The Bland-Altman plots indicated good agreement between actual and estimated VO2peak. The mean absolute prediction error was 11.9%.

CONCLUSIONS

Musculoskeletal fitness and anthropometric components may be predictive factors of a new conceptual modality estimating concomitant cardiorespiratory fitness beyond their traditional health-related indications.

Short-term effects of upper extremity circuit resistance training on muscle strength and functional independence in patients with paraplegia

BACKGROUND AND OBJECTIVES

A number of exercises to strengthen the upper extremities are recommended to increase functional independence and quality of life (QoL) in patients with paraplegia. Circuit resistance training (CRT) is a type of progressive resistive exercise performed repeatedly at fixed mechanical exercise stations. The aim of this study was to investigate the potential benefits of CRT for upper extremity muscle strength, functional independence, and QoL in patients with paraplegia.

MATERIALS AND METHODS

Twenty-six patients with paraplegia who were participating in a conventional rehabilitation program at a tertiary education and research hospital were enrolled in this study. The participants were randomly assigned to two groups. The exercise group participated in the CRT program, which consisted of repetitive exercises for the upper extremities performed at fixed mechanical stations 5 sessions per week for 6 weeks, in addition to conventional rehabilitation. Participants in the control group received only conventional rehabilitation over the same period. We compared the groups with respect to QoL, as well as isokinetic muscle test outcomes in the upper extremities, using the Functional Independence Measure (FIM) and Borg's scale.

RESULTS

We observed significant increases in scores on the physical component of the FIM, Borg's scale, and QoL in both the exercise and control groups. Furthermore, the large majority of isokinetic values were significantly more improved in the exercise group compared to the control group. When post-treatment outcomes were compared between the groups, improvements in scores on the physical component of the FIM and in most isokinetic values were significantly greater in the exercise group.

CONCLUSIONS

This study showed that CRT has positive effects on muscle strength in the upper extremities and the physical disability components of the FIM when added to conventional rehabilitation programs for paraplegic patients. However, we observed no significant improvement in QoL scores after adding CRT to a conventional treatment regime.

LEVEL OF EVIDENCE

Randomized trial (Level II).

Influence of Relative Strength on Functional Independence of Patients With Spinal Cord Injury

OBJECTIVE

To investigate the influence of strength values and fat mass on functional independence of men with different spinal cord injury (SCI) levels.

DESIGN

Cross-sectional study.

SETTING

Hospital network.

PARTICIPANTS

Men with SCI (N=45).

INTERVENTIONS

Subjects were assessed in functional independence scales, a 1 repetition maximum (1RM) test, and body composition to detect absolute and relative strength: 1RM divided by body mass (BM) and lean body mass (LBM), respectively.

MAIN OUTCOME MEASURES

Stepwise multiple regression analysis was used to verify the influence of predictors on functional independence (FIM and Spinal Cord Independence Measure [SCIM] scale and subscales). Receiver operating characteristic curves were created to identify cutoff points of strength for functional independence.

RESULTS

The best models for FIM total, FIM mobility, and SCIM total used 1RM as the best predictor (adjusted R²=.75, .67, and .65, respectively; P<.05). Relative strength (1RM/LBM) was the best predictor for SCIM mobility (adjusted R²=.62, P<.05). A FIM score of 69 has a 1RM cutoff point of 50.1kg, and a FIM score of 76 has cutoff points of .73 for 1RM/BM and .91 for 1RM/LBM. A SCIM score of 68 has cutoff points for 1RM, 1RM/BM, and 1RM/LBM of 50.1kg, .77, and .92, respectively.

CONCLUSIONS

Cutoff points of relative strength should be used as determinant variables for independence, health, or sports performance. This study may contribute to more adequate guidance of physical activity during a rehabilitation program and after discharge.

Determination of a strength index for upper body local endurance strength in sedentary individuals: a cross sectional analysis

A range of balance between flexor and extensor muscles is fundamental in order to prevent pathologies caused by bad postures or to ensure health of the joint as a measure of prevention of overtraining in specific muscle groups. Therefore, the aim of this study is to examine the ratio between "pulling" and "pushing" strength in sedentary individuals. 212 healthy participants, of both genders (139 male and 73 female; age 32 ± 13.3 years, weight 70.2 ± 14.1 kg, height 173 ± 9 cm) were retained for investigation. Strength was assessed through a new methodology: Pulling through a lat-pulldown test while pushing strength through a chest-press test. Both tests were performed to exhaustion with an overload of 30 % of each participants bodyweight. Such method aims to prevent excessive overloads in sedentary individuals. Pearson's correlations and a t test to assess differences were analyzed. Subsequently, the ratio for both genders of pulling and pushing local endurance strength was assessed by means. A mean number of 57 repetitions was shown with the lat-pulldown while 34 repetition with the chest press. A correlation of 0.42 has been found between the number of repetitions of the two tests. A significant difference (p < 0.001) was found between such performances. No correlation was found between the strength measures and the anthropometric parameters of the participants. The lat machine to chest press ratio was 1.36:1 for male while 2.69:1 for female. The results indicate that sedentary participants have higher pulling rather than pushing local endurance strength. Such ratio should be considered as a normative value when starting to perform exercise protocols. Resistance training should be performed in order to improve strength measures of the weaker muscles and reduce such ratio.

Evaluation of muscle fatigue of wheelchair basketball players with spinal cord injury using recurrence quantification analysis of surface EMG

Wheelchair basketball is the most popular exercise activity among individuals with spinal cord injury (SCI). The purpose of this study was to investigate muscular endurance and fatigue in wheelchair basketball athletes with SCI using surface electromyography (SEMG) and maximal torque values. SEMG characteristics of 10 wheelchair basketball players (WBP) were compared to 13 able-bodied basketball players and 12 sedentary able-bodied subjects. Participants performed sustained isometric elbow flexion at 50% maximal voluntary contraction until exhaustion. Elbow flexion torque and SEMG signals were recorded from three elbow flexor muscles: biceps brachii longus, biceps brachii brevis and brachioradialis. SEMG signals were clustered into 0.5-s epochs with 50% overlap. Root mean square (RMS) and median frequency (MDF) of SEMG signals were calculated for each muscle and epoch as traditional fatigue monitoring. Recurrence quantification analysis was used to extract the percentage of determinism (%DET) of SEMG signals. The slope of the %DET for basketball players and WBP showed slower increase with time than the sedentary able-bodied control group for three different elbow flexor muscles, while no difference was observed for the slope of the %DET between basketball and WBP. This result indicated that the athletes are less fatigable during the task effort than the nonathletes. Normalized MDF slope decay exhibited similar results between the groups as %DET, while the slope of the normalized RMS failed to show any significant differences among the groups (p > 0.05). MDF and %DET could be useful for the evaluation of muscle fatigue in wheelchair basketball training. No conclusions about special training for WBP could be determined.

Effects of chest physiotherapy and aerobic exercise training on physical fitness in young children with cystic fibrosis

BACKGROUND

Cystic fibrosis is a multisystem disease where the main problems are existing in the respiratory system. Aerobic exercise programs are effective in increasing physical fitness and muscle endurance in addition to chest physiotherapy.

OBJECTIVE

The aim of this study was to evaluate the effects of chest physiotherapy and aerobic exercise training on physical fitness in young children with cystic fibrosis.

METHODS

Sixteen patients with cystic fibrosis, between the ages 5-13 years, were included in this study. All children were assessed at the beginning and at the end of 6 week of the training. Modified Bruce protocol was used for assessing the cardiovascular endurance. The sit-up test was used to evaluate the dynamic endurance of abdominal muscles, standing long jump was used to test power, sit and reach, trunk lateral flexion, trunk hyperextension, trunk rotation and forward bending tests were used to assess flexibility, 20 m shuttle run test and 10-step stair climbing tests were used to assess power and agility. All patients received chest physiotherapy and aerobic training, three days a week for six weeks. Active cycle of breathing technique and aerobic exercise training program on a treadmill were applied.

RESULTS

By evaluating the results of the training, positive progressions in all parameters except 20 m shuttle run and 10 stairs climbing tests were observed (p < 0.05). Active cycle of breathing techniques were used together with exercise training in clinically stable cystic fibrosis patients increases thoracic mobility (p < 0.05) and the physical fitness parameters such as muscle endurance, strength and speed (p < 0.05). Comparison of the results in sit and reach and forward bending tests were not significant (p > 0.05).

CONCLUSION

It is thought that in addition to medical approaches to the systems affected, the active cycle of breathing techniques along with aerobic training helps to enhance the aerobic performance, thoracic mobility and improves physical fitness in children with cystic fibrosis.

Comparison of training methods to improve walking in persons with chronic spinal cord injury: a randomized clinical trial

OBJECTIVE

To compare two forms of device-specific training - body-weight-supported (BWS) ambulation on a fixed track (TRK) and BWS ambulation on a treadmill (TM) - to comprehensive physical therapy (PT) for improving walking speed in persons with chronic, motor-incomplete spinal cord injury (SCI).

METHODS

Thirty-five adult subjects with a history of chronic SCI (>1 year; AIS 'C' or 'D') participated in a 13-week (1 hour/day; 3 days per week) training program. Subjects were randomized into one of the three training groups. Subjects in the two BWS groups trained without the benefit of additional input from a physical therapist or gait expert. For each training session, performance values and heart rate were monitored. Pre- and post-training maximal 10-m walking speed, balance, muscle strength, fitness, and quality of life were assessed in each subject.

RESULTS

All three training groups showed significant improvement in maximal walking speed, muscle strength, and psychological well-being. A significant improvement in balance was seen for PT and TRK groups but not for subjects in the TM group. In all groups, post-training measures of fitness, functional independence, and perceived health and vitality were unchanged.

CONCLUSIONS

Our results demonstrate that persons with chronic, motor-incomplete SCI can improve walking ability and psychological well-being following a concentrated period of ambulation therapy, regardless of training method. Improvement in walking speed was associated with improved balance and muscle strength. In spite of the fact that we withheld any formal input of a physical therapist or gait expert from subjects in the device-specific training groups, these subjects did just as well as subjects receiving comprehensive PT for improving walking speed and strength. It is likely that further modest benefits would accrue to those subjects receiving a combination of device-specific training with input from a physical therapist or gait expert to guide that training.

Using robot-applied resistance to augment body-weight-supported treadmill training in an individual with incomplete spinal cord injury

BACKGROUND AND PURPOSE

The efficacy of task-specific gait training for people with spinal cord injury (SCI) is premised on evidence that the provision of gait-related afferent feedback is key for the recovery of stepping movements. Recent findings have shown that sensory feedback from flexor muscle afferents can facilitate flexor muscle activity during the swing phase of walking. This case report was undertaken to determine the feasibility of using robot-applied forces to resist leg movements during body-weight-supported treadmill training (BWSTT) and to measure its effect on gait and other health-related outcomes.

CASE DESCRIPTION

The patient described in this case report was a 43-year-old man with a T11 incomplete chronic SCI. He underwent 36 sessions of BWSTT using a robotic gait orthosis to provide forces that resist hip and knee flexion.

OUTCOMES

Tolerance to the training program was monitored using the Borg CR10 scale and heart rate and blood pressure changes during each training session. Outcome measures (ie, 10-Meter Walk Test, Six-Minute Walk Test, modified Emory Functional Ambulation Profile [mEFAP], Activities-specific Balance Confidence Scale, and Canadian Occupational Performance Measure) were completed and kinematic parameters of gait, lower-extremity muscle strength (force-generating capacity), lower-limb girth, and tolerance to orthostatic stress were measured before and after the training program.

DISCUSSION

The patient could tolerate the training. Overground walking speed, endurance, and performance on all subtasks of the mEFAP improved and were accompanied by increased lower-limb joint flexion and toe clearance during gait. The patient's ambulatory self-confidence and self-perceived performance in walking also improved. These findings suggest that this new approach to BWSTT is a feasible and potentially effective therapy for improving skilled overground walking performance.

Effects of resistance and endurance training in persons with paraplegia

INTRODUCTION

The specific effects of resistance and endurance training on upper extremity work capacity, muscular strength, and anaerobic power in chronic survivors of paraplegia have not been previously determined.

PURPOSE

This study compared the effects of 12 wk of endurance training (ET) with 12 wk of resistance training (RT) on VO(2peak), upper extremity strength, and power output in persons with chronic paraplegia.

METHODS

Eighteen subjects with neurologically complete paraplegia, T6-T10, participated in three weekly exercise sessions during a 12-wk training period. Subjects were matched into pairs (body mass and gender) and were randomly assigned to ET or RT. The ET group performed 30 min of arm cranking at 70%-85% of HR(peak). The RT group performed three sets of 10 repetitions at six exercise stations with an intensity of ranging from 60% to 70% of 1 repetition maximum (1RM). Values of upper extremity strength (1RM) were established using the Mayhew regression equation. VO(2peak) was determined during arm ergometry testing using open circuit spirometry. Arm Wingate anaerobic testing (WAnT) was used to determine subjects' peak and mean anaerobic power output.

RESULTS

VO(2peak) values were significantly greater after RT (15.1%) and ET (11.8%). Muscular strength significantly increased for all exercise maneuvers in the RT group (P values < 0.01) with no changes detected in the ET group. Mean WAnT power increased in the RT and ET groups by 8% and 5%, respectively. The RT group displayed significantly greater gains in peak WAnT power (P < 0.001) than ET, 15.6% and 2.6%, respectively.

CONCLUSION

Persons with paraplegia can significantly improve their upper extremity work capacity, muscular strength, and power by participating in RT.

Comparison of heart rate response to tennis activity between persons with and without spinal cord injuries: implications for a training threshold

The purpose of this study was to evaluate the ability of individuals with spinal cord injury (SCI) to reach a training threshold during on-court sport activity. Monitors collected heart rate (HR) data every 5 s for 11 wheelchair tennis players (WCT) with low paraplegia and 11 able-bodied controls matched on experience and skill level (ABT). Average HR was determined for time spent in practice (e.g, drills) and game (i.e., a competitive set), and the ability to surpass 50% peak HR (HRpeak) and 64% HRpeak in each condition was evaluated. Average exercise intensity (%HRpeak) was not significantly different between the groups during practice (M WCT = 68.18, SD = 7.53%, M ABT = 68.78, SD = 5.44%; t = .22, p = .83) or game (M WCT = 68.17, SD = .17%, M ABT = 71.55, SD = 4.75%; t = 1.12, p =.28). Allparticipants averaged an intensity > or = 50% HR-peak during practice and game, and the difference between group participants averaging an intensity > or = 64% HRpeak was not significant during practice (chi2 = .92, p = .34) or game (chi2 = 3.85, p = .05). In terms of reaching a health and fitness training threshold during tennis, individuals with low-level SCI are similar to matched controls.

Health-related physical fitness of adolescents and young adults with myelomeningocele

To assess components of health-related physical fitness in adolescents and young adults with myelomeningocele (MMC), and to study relations between aerobic capacity and other health-related physical fitness components. This cross-sectional study included 50 adolescents and young adults with MMC, aged 16–30 years (25 males). Aerobic capacity was quantified by measuring peak oxygen uptake (peakVO₂) during a maximal exercise test on a cycle or arm ergometer depending on the main mode of ambulation. Muscle strength of upper and lower extremity muscles was assessed using a hand-held dynamometer. Regarding flexibility, we assessed mobility of hip, knee and ankle joints. Body composition was assessed by measuring thickness of four skin-folds. Relations were studied using linear regression analyses. Average peakVO₂ was 1.48 ± 0.52 l/min, 61% of the participants had subnormal muscle strength, 61% had mobility restrictions in at least one joint and average sum of four skin-folds was 74.8 ± 38.8 mm. PeakVO₂ was significantly related to gender, ambulatory status and muscle strength, explaining 55% of its variance. Adolescents and young adults with MMC have poor health-related physical fitness. Gender and ambulatory status are important determinants of peakVO₂. In addition, we found a small, but significant relationship between peakVO₂ and muscle strength.

Effects of circuit resistance training on fitness attributes and upper-extremity pain in middle-aged men with paraplegia

OBJECTIVE

To examine the effects of circuit resistance exercise (CRT) training on muscle strength, endurance, anaerobic power, and shoulder pain in middle-aged men with paraplegia.

DESIGN

Repeated testing.

SETTING

Academic medical center.

PARTICIPANTS

Seven men (age range, 39-58y) with motor-complete paraplegia from T5 to T12 and confirmed shoulder pain occurring during daily activities.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Subjects underwent a 4-month CRT program using alternating resistance maneuvers and high-speed, low-resistance arm exercise. One-repetition maximal force was measured before training and monthly thereafter. Pretraining and posttraining peak oxygen uptake (Vo(2)peak) was measured by graded arm testing. Anaerobic power was measured before and after training using a 30-second Wingate Anaerobic Test. Shoulder pain was self-evaluated by an index validated for people with spinal cord injury (Wheelchair Users Shoulder Pain Index [WUSPI]).

RESULTS

Strength increases ranging from 38.6% to 59.7% were observed for all maneuvers (P range, .005-.008). Vo(2)peak increased after training by 10.4% (P=.01), and peak and average anaerobic power increased by 6% (P=.001) and 8.6% (P=.005), respectively. WUSPI scores +/- standard deviation were lowered from 31.9+/-24.8 to 5.7+/-5.9 (P=.008), with 3 of 7 subjects reporting complete resolution of shoulder pain.

CONCLUSIONS

CRT improves muscle strength, endurance, and anaerobic power of middle-aged men with paraplegia while significantly reducing their shoulder pain.

Aerobic fitness and upper extremity strength in patients aged 11 to 21 years with spinal cord dysfunction as compared to ideal weight and overweight controls

OBJECTIVE

To determine whether the aerobic fitness, upper extremity strength, and body composition in groups of adolescents with mobility impairment due to thoracic and upper lumbar spinal cord injury (SCI) or spina bifida (SB) are significantly different from those in groups of adolescents without mobility impairment who are of normal weight (CTRL) or overweight (OW).

SUBJECTS

One hundred fifteen total subjects were evaluated including 59 female (19 SB, 9 SCI, 17 OW, and 14 CTRL) and 56 male (18 SB, 10 SCI, 8 OW, and 20 CTRL) participants aged 11 to 21 years.

METHODS

Aerobic fitness was assessed using a ramp protocol with a magnetically braked arm ergometer. Heart rate and oxygen uptake (VO2) were recorded. Peak isokinetic upper arm and shoulder strength values were determined with a dynamometer. Body composition was estimated using dual energy x-ray absorptiometry (DEXA). Male and female subjects were categorized as overweight if their percent body fat by DEXA exceeded 25% and 30%, respectively. Results were analyzed with an ANOVA using the Bonferroni correction. Significance was accepted at P < 0.05.

RESULTS

The percent body fat of both the male and female SB and SCI subjects was significantly higher than CTRL but was not different than OW. In general, the shoulder extension and flexion strength in both the SB and SCI males and females was significantly lower than that of the CTRL and OW. The SCI and SB subjects had significantly reduced aerobic capacity (VO2/kg) compared to the CTRL subjects but were not different than the OW subjects. During the maximal exercise test, the SB and SCI subjects reached exhaustion at significantly lower workloads than the CTRL and OW subjects.

CONCLUSIONS

Patients age 11 to 21 years with SB and SCI had reduced aerobic capacity that was associated with being overweight and having reduced upper extremity strength. These data suggest that interventions to increase strength and fitness and to manage weight should be recommended in this population.

La fatigue du blessé médullaire

OBJECTIVES

To identify variables increasing fatigue following spinal cord injury (SCI) and their functional consequences.

METHODS

A search of the Medline and Reedoc databases with the keywords SCI, fatigue, intrinsic muscular fatigue, chronic fatigue, aging, training, electrostimulation, quality of life and the same words in French.

RESULTS

Two kinds of fatigue are identified following SCI. Intrinsic fatigue in muscles totally or partially paralysed at the level of or below the spinal cord lesion; this peripheral fatigue is due to denervation, total or partial loss of motoneurons, or histological and metabolical changes in muscle; it is well-defined by electrophysiological technology; spasticity and spasms have little influence on its development; it is reversible in part with long term electrostimulation, but at this time, electroneuroprosthetic techniques do not reduce the excessive energetic cost to stand up and walk. Chronic fatigue appears in the long term following SCI; it is linked with aging, physiological, and psychological deconditioning; some data point to chronic fatigue after SCI similar to post-polio syndrome and chronic fatigue syndrome, which may explain the central nature of the fatigue; training programs could be useful in delaying this chronic fatigue and as a consequence, increasing the latent quality of life.

CONCLUSION

Muscular intrinsic fatigue after SCI is always of a peripherical nature in muscles partially or totally paralysed. Chronic fatigue during aging greatly decreases quality of life. Both intrinsic and chronic fatigue could be anticipated by electrostimulation technique on the one hand and long term training on the other.

Changes in Physical Capacity During and After Inpatient Rehabilitation in Subjects With a Spinal Cord Injury

OBJECTIVE

To assess changes in physical capacity and its determinants in persons with a spinal cord injury.

DESIGN

Prospective cohort study. Measurements at the start of active rehabilitation (t1), 3 months later (t2), at discharge (t3), and 1 year after discharge (t4).

SETTING

Eight rehabilitation centers in The Netherlands.

PARTICIPANTS

A total of 186 subjects at t1 and 123 subjects at t4.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Peak aerobic power output (POpeak), peak oxygen uptake (V(O2)peak), muscle strength of the upper extremity (manual muscle test, handheld dynamometry), and respiratory function (forced expiratory flow per second, forced vital capacity).

RESULTS

Random coefficient analysis demonstrated that the POpeak, V(O2)peak, strength, and respiratory function improved during inpatient rehabilitation, and that V(O2)peak, strength, and respiratory function continued to improve after discharge. Age, sex, and level and completeness of lesion were determinants of the change in components of physical capacity.

CONCLUSIONS

Physical capacity improves during inpatient rehabilitation, and some components continue to improve after discharge. Subpopulations have a different level of (change in) physical capacity. The components of physical capacity are related; intervention studies are needed to confirm whether training 1 component could improve another component.