Reduced muscle power is associated with slower walking velocity and falls in people with Parkinson's disease

Differences in power and performance during sit-to-stand test and its relationships to functional measures in older adults with and without Parkinson's disease

AIMS

i) to compare 30-s sit-to-stand (STS) test repetitions and power between older adults with and without Parkinson's disease (PD) and ii) to evaluate the relationship of STS repetitions and power with functional measures in older people with PD.

METHODS

STS repetitions and power (Alcazar's equation) during the 30-s STS test were assessed in forty-six age- and sex-matched older adults with and without PD. Functional measures included habitual (HGS) and maximum gait speed (MGS), timed-up-and-go (TUG) test and the Mini-Balance Evaluation System Test (Mini-BEST). PD-specific tests were as follows: the motor subscale of the Unified Parkinson's Disease Rating Scale (UPDRS-III), quality of life [Parkinson's Disease Questionnaire (PDQ-39)], perceived freezing of gait (FOG questionnaire), and fear of falling [Falls Efficacy Scale (FES)]. T scores, repeated measures ANOVA and linear regression analyses were used.

RESULTS

T scores for older adults with PD were - 2.7 ± 4.5 for STS repetitions, -5.2 ± 4.2 for absolute STS power, and - 3.1 ± 4.6 for relative STS power compared to older adults without PD. T scores for absolute STS power were lower than T scores for STS repetitions (p < 0.001) and relative STS power (p < 0.001). Both absolute and relative STS power and STS repetitions showed similar correlations with functional measures (r = 0.44 to 0.59; both p < 0.05). Relative STS power (r = -0.55; p < 0.05) and STS repetitions (r = -0.47 to -0.55; p < 0.05) but not absolute STS power were correlated to PD-specific tests.

CONCLUSIONS

STS repetitions and power values estimated through the 30-s STS test were lower in older people with PD than without PD. Overall, STS power measures were similarly associated with functional performance as STS repetitions, indicating these power equations can be implemented when assessing lower extremity function in older people with PD.

Velocity-Based-Training Frequency Impacts Changes in Muscle Morphology, Neuromuscular Performance, and Functional Capability in Persons With Parkinson's Disease

ABSTRACT

Calaway, C, Walls, K, Levitt, H, Caplan, J, Mann, B, Martinez, K, Gastaldo, R, Haq, I, and Signorile, JF. Velocity-based-training frequency impacts changes in muscle morphology, neuromuscular performance, and functional capability in persons with Parkinson's disease. J Strength Cond Res XX(X): 000-000, 2024-Velocity-based training (VBT) positively impacts muscle morphology and performance in persons with Parkinson's disease (PD); however, optimal training frequencies for VBT in patients with PD remain undetermined. Changes in ultrasound-determined muscle thickness (MT) and echo intensity (EI)-derived muscle quality of the rectus femoris (RF) and vastus lateralis (VL), neuromuscular performance, and functional capacity were examined following 2 VBT frequencies (2-3 d·wk -1 ) using 30% velocity loss thresholds for 12 weeks. Neuromuscular performance was assessed using computerized pneumatic resistance machines. For each variable, 2 (time) × 2 (group) repeated-measures analyses of variance (ANOVA) were used to determine significant main effects and interactions. Significant time effects were seen for MT and EI of all muscles ( p < 0.05). Muscle thickness improvements included right VL (RVL) (0.171 ± 0.065 cm; p = 0.019), left VL (LVL) (0.214 ± 0.101 cm; p = 0.049), right RF (RRF) (0.194 ± 0.077 cm; p = 0.023), and left RF (LRF) (0.318 ± 0.109 cm; p = 0.010). For EI, improvements occurred in RVL (-18.688 ± 3.600; p = <0.001), LVL (-10.959 ± 4.894; p = 0.040), RRF (-9.516 ± 3.537; p = 0.016), and LRF (-9.018 ± 3.444; p = 0.019). Time effects were seen for leg-press 1-repetition maximum and peak power ( p < 0.01) and habitual walking speed ( p = 0.022), with a group by time interaction for maximal gait speed favoring the 3 d·wk -1 condition (∆0.15 m·s -1 , p = 0.002). The results indicate that VBT at 2 or 3 d·wk -1 can significantly improve muscle morphology, neuromuscular performance, and functional capability in patients with PD; however, improvements in maximal gait speed require 3 d·wk -1 . These findings provide flexibility when developing exercise prescriptions for patients with PD.

The Impact of Velocity-Based Training on Load-Velocity Relationships in Leg Press and Chest Press for Older Persons

ABSTRACT

Calaway, C, Mishra, S, Parrino, R, Martinez, KJ, Mann, JB, and Signorile, JF. Velocity-based training affects the load-velocity relationship in leg press and chest press for older persons. J Strength Cond Res 38(6): 1136-1143, 2024-This study examined the impact of 3 months of velocity-based training (VBT) on chest press (CP) and leg press (LP) maximal strength (1 repetition maximum [1RM]), peak power (PP), and percentage load where PP was achieved (%1RMPP) in older adults. Twenty-nine subjects were assigned to either a velocity-deficit (VD) group or a force-deficit (FD) group for each exercise depending on their load-velocity (LV) curves. Changes in load were determined by the ability to maintain either 90% (VD) or 70% (FD) of their PP during training. Subjects' powers were tested before and after the training intervention at loads between 40 and 80%1RM. Separate 2 (group) × 2 (time) ANOVA was used to examine changes in each variable by group for each exercise. Wilcoxon signed-rank tests were used to determine whether significant changes in %1RMPP for each exercise and group. For chest press 1 repetition maximum, there were no significant main effects or interaction. Significant main effects for time were observed for leg press 1 repetition maximum ( p < 0 .001, η2 = 0.547) and chest press peak power ( p = 0.009, η2 = 0.243). For LPPP, there were no significant main effects or interactions. For %1RMPP, CP median scores revealed no significant changes for either group. Significant declines in %1RMPP were observed for leg press velocity-deficit and leg press force-deficit ( p < 0.03) groups. Velocity-based training was effective at improving 1RM, PP, and shifting %1RMPP in the LP groups. These results have implications for targeting power improvements at specific areas of the LV curve. Health care providers and trainers should consider these findings when constructing exercise programs to counter age-related declines in older adults.

Are physical activity levels, cardiorespiratory fitness and peak power associated with Parkinson's disease severity?

INTRODUCTION

Increased physical activity (PA) may slow Parkinson's disease (PD) progression. Associations between markers of PA and PD severity could justify further studies evaluating interventions increasing PA levels in PD. The objectives of the present study were to assess associations between PA, cardiorespiratory fitness (VO2-max), and muscle peak power and measures of the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS), the Parkinson's disease questionnaire-39 (PDQ-39), and the four PD hallmark motor symptoms (rigidity, bradykinesia, postural instability, and tremor).

METHODS

Data from 105 people with PD were used. PA was measured for seven consecutive days using accelerometers. Peak power was measured with a linear encoder during a chair rise test, while VO2-max was directly assessed during a graded bicycle test. Analyses included simple and multiple linear regression and hurdle exponential regression.

RESULTS

PA was weakly to moderately associated with MDS-UPDRS II + III, rigidity, bradykinesia, and postural instability, as well as PDQ-39 mobility and activities of daily living sub-scores. VO2-max and peak power were weakly to moderately associated with MDS-UPDRS III, bradykinesia, and postural instability, while peak power was further weakly associated with the MDS-UPDRS II. Lastly, VO2-max was associated with PDQ-39 mobility and activities of daily living sub-scores.

CONCLUSION

PA, VO2-max, and peak power were associated with PD severity, thus highlighting the potential benefits of a physically active lifestyle. Furthermore, PA and VO2-max were associated with PDQ-39 sub-scores. This calls for confirmation of the potential effect of PA on quality of life in PD.

Validity and reliability of linear encoder muscle power testing in persons with Parkinson's disease

OBJECTIVE

To investigate the construct validity ON medication and the reliability both ON and OFF medication of linear encoder muscle power testing in persons with Parkinson's disease (pwPD).

DESIGN

A study using baseline data from one randomized controlled trial (study 1) and one cohort study (study 2).

SETTING

University exercise lab.

PARTICIPANTS

Study 1: 35 healthy controls and 70 pwPD. Study 2: 20 pwPD.

INTERVENTION

Study 1: baseline data. Study 2: 4 chair rise tests (2 ON and 2 OFF medication), in a randomized order, separated by 4 to 16 days.

MAIN MEASURES

Linear encoder data were collected from a chair rise test. Known groups validity and convergent validity (i.e., construct validity) were assessed by comparing peak power between pwPD and healthy controls and associations between peak power and functional performance (i.e., 6-Min Walk Test, Timed Up and Go Test, Six-Spot Step Test), respectively. Reliability was assessed as day-to-day variation and by intraclass correlation coefficients.

RESULTS

Peak power was comparable between pwPD and healthy controls (-7.2%, p = 0.17), but lower in moderately impaired pwPD compared to mildly impaired pwPD (-27%, p < 0.01) and healthy controls (-23%, p < 0.01). Moderate to strong associations were observed between peak power and functional performance (r2 = 0.44-0.51). Day-to-day variation ON and OFF medication were 1.0 and 1.3 W/kg, respectively, while intraclass correlation coefficients were 0.95 (0.87;0.98) and 0.93 (0.82;0.97), respectively.

CONCLUSION

Linear encoder muscle power testing shows inconsistent known groups validity, acceptable convergent validity ON medication, and excellent day-to-day reliability ON and OFF medication in pwPD.

Prognostic factors for falls in Parkinson's disease: a systematic review

BACKGROUND

Falls represent a critical concern in Parkinson's disease (PD), contributing to increased morbidity and reduced quality of life.

PURPOSE

We conducted a systematic review to assess the prognostic factors associated with falls in PD, aiming to provide a comprehensive overview of relevant demographic and clinical parameters, and aid neurologists in identifying subsets of PD patients most susceptible to falls and associated injuries.

METHODS

PubMed and Web of Science databases were searched for prospective studies assessing factors associated with falls in ambulatory PD patients across different settings, from inception to August 2023. Data extraction was conducted using CHARMS-PF checklist and risk of bias was assessed with QUIPS tool. PRISMA guidelines were followed.

RESULTS

The initial search yielded 155 references. Thirty-four studies, involving a total of 3454 PD patients, were included in the final analysis. The mean pooled age was 67.6 years, and 45.1% were women. PD patients presented mild motor impairment (UPDRS III score 27.8) with mean pooled disease duration of 5.7 years. Gait and balance disorders and history of prior falls emerged as the most consistent predictors of falls across studies. Disease duration, disease severity, dysautonomic symptoms, freezing of gait, frontal cognitive functions, and PD medication dosages yielded inconsistent findings. Conversely, dyskinesias, age, sex, and depression were unrelated to future falls in PD. Logistic regression models were most commonly employed to identify factors significantly associated with falls in PD. Substantial heterogeneity prevailed in the inclusion of confounding factors.

CONCLUSION

The evidence suggests that previous history of falls, gait disorders, and poor balance are robust prognostic markers for falls in PD.

Impaired skeletal muscle health in Parkinsonian syndromes: clinical implications, mechanisms and potential treatments

There is increasing evidence that neurodegenerative disorders including the Parkinsonian syndromes are associated with impaired skeletal muscle health, manifesting as wasting and weakness. Many of the movement problems, lack of muscle strength and reduction in quality of life that are characteristic of these syndromes can be attributed to impairments in skeletal muscle health, but this concept has been grossly understudied and represents an important area of unmet clinical need. This review describes the changes in skeletal muscle health in idiopathic Parkinson's disease and in two atypical Parkinsonian syndromes, the most aggressive synucleinopathy multiple system atrophy, and the tauopathy progressive supranuclear palsy. The pathogenesis of the skeletal muscle changes is described, including the contribution of impairments to the central and peripheral nervous system and intrinsic alterations. Pharmacological interventions targeting the underlying molecular mechanisms with therapeutic potential to improve skeletal muscle health in affected patients are also discussed. Although little is known about the mechanisms underlying these conditions, current evidence implicates multiple pathways and processes, highlighting the likely need for combination therapies to protect muscle health and emphasizing the merit of personalized interventions for patients with different physical capacities at different stages of their disease. As muscle fatigue is often experienced by patients prior to diagnosis, the identification and measurement of this symptom and related biomarkers to identify early signs of disease require careful interrogation, especially for multiple system atrophy and progressive supranuclear palsy where diagnosis is often made several years after onset of symptoms and only confirmed post-mortem. We propose a multidisciplinary approach for early diagnosis and implementation of personalized interventions to preserve muscle health and improve quality of life for patients with typical and atypical Parkinsonian syndromes.

Association of activities of daily living, mobility and balance ability, and symptoms of Parkinson's disease with the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles in patients with Parkinson's disease

PURPOSE

We examined the association of activities of daily living (ADL), mobility and balance ability, and symptoms of Parkinson's disease (PD) with the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles in patients with PD.

METHODS

The subjects were 11 community-dwelling patients with PD. ADL were assessed using the Functional Independence Measure. Mobility capacity was assessed based on measurement of maximal walking speed and timed up-and-go time, while balance ability was evaluated based on measurement of one-legged stance time. The symptoms of PD were assessed based on measurement of the Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale. Muscle thickness (MT) and echo intensity (EI) of the trunk and lower extremity muscles were also measured using an ultrasound imaging device.

RESULTS

Partial correlation analysis revealed an association between reduced ADL and increased EI of the lumbar erector spinae muscle; reduced mobility capacity and increased EI of the rectus abdominis and gluteus minimus muscles; and reduced balance ability and decreased MT of the lumbar erector spinae muscle and increased EI of the lumbar erector spinae, semitendinosus, and tibialis posterior muscles. Partial correlation analysis also showed an association between symptoms of severe PD and decreased MT of the tibialis anterior muscles and increased EI of the lumbar erector spinae, gluteus minimus, and tibialis posterior muscles.

CONCLUSION

The properties of the trunk and lower extremity muscles may be critical for ADL, mobility and balance ability, and symptoms of PD in patients with PD.

Association between walking speed and calcaneus stiffness index in older adults

INTRODUCTION

The aim here is to examine the association between objectively measured usual walking speed (UWS) and bone status in community-dwelling older Chinese.

MATERIALS AND METHODS

This is a cross-sectional study of a population of 1528 adults (817 females, mean age 68.5 ± 5.3; 711 males, mean age 69.1 ± 5.2) aged 60-79, living in communities in Shanghai. Walking speed was assessed using a 4-m walk test at a usual-pace walking speed a walking speed at which the subject felt relaxed-and bone status measured by quantitative ultrasound (QUS). The health-related characteristics of participants include family background, physical activity level, chronic disease, smoking and alcohol consumption, frequency of falls, vitamin intake, and hormone therapy.

RESULTS

Multiple linear regression is used to analyses any association between UWS and bone status, adjusting for confounding factors showing a significant association between faster UWS and a higher calcaneal stiffness index (SI) (p < 0.01). Comparing the lowest quartile of the data set with the highest at UWS, a high SI is achieved with 5.34 (95% CI = 3.22, 7.46) (p < 0.01), after adjusting for confounders. An increase of 1 dm/s was associated with a 0.91 (95% CI = 0.53, 1.29) increase in SI. This relationship for most subgroups is consistent.

CONCLUSION

Our findings suggest that UWS can be a sensitive indicator of calcaneal bone loss among an older population.

Muscle shape changes in Parkinson's disease impair function during rapid contractions

AIM

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized, among the others, by muscle weakness. PD patients reach lower values of peak torque during maximal voluntary contractions but also slower rates of torque development (RTD) during explosive contractions. The aim of this study was to better understand how an impairment in structural/mechanical (peripheral) factors could explain the difficulty of PD patients to raise torque rapidly.

METHODS

Participants (PD patients and healthy matched controls) performed maximum voluntary explosive fixed-end contraction of the knee extensor muscles during which dynamic muscle shape changes (in muscle thickness, pennation angle, and belly gearing: the ratio between muscle belly velocity and fascicle velocity), muscle-tendon unit (MTU) stiffness and EMG activity of the vastus lateralis (VL) were investigated. Both the affected (PDA) and less affected limb (PDNA) were investigated in patients.

RESULTS

Control participants reached higher values of peak torque and showed a better capacity to express force rapidly compared to patients (PDA and PDNA). EMG activity was observed to differ between patients (PDA) and controls, but not between controls and PDNA. This suggests a specific neural/nervous effect on the most affected side. On the contrary, MTU stiffness and dynamic muscle shape changes were found to differ between controls and patients, but not between PDA and PDNA. Both sides are thus similarly affected by the pathology.

CONCLUSION

The higher MTU stiffness in PD patients is likely responsible for the impaired muscle capability to change in shape which, in turn, negatively affects the torque rise.

Hip Abductor Power and Velocity: Reliability and Association With Physical Function

ABSTRACT

Lanza, MB, Jin, KH, Karl, H, Myers, J, Ryan, E, and Gray, VL. Hip abductor power and velocity: reliability and association with physical function. J Strength Cond Res 37(2): 284-290, 2023-Muscle power, defined as the ability of the muscle to produce torque quickly, has received little attention and may be critical for understanding physical function and performance. Hip abductors' capacity to produce power through both torque and velocity is important for different human activities; hence, a reliable assessment of hip abduction is critical. The first aim of the study was to assess the intersession reliability of hip abductor muscles maximal torque and submaximal power and power during standing hip abduction in young adults using pneumatic resistance. A secondary aim was to investigate whether there was a relationship between hip abductor maximal torque and submaximal power and velocity with clinical assessments of strength and power in young adults. The subjects (n = 24; 26.0 ± 3.7 years) visited the laboratory 2 times. In the first visit, the subjects performed on a pneumatic resistance machine 1-repetition maximum (1RM) and submaximal tests (40, 60, and 70% of 1RM) of the hip abductors and clinical tests of lower-extremity strength and power (The 30-second chair stand test [30CST]; and stair climb power test). During the second visit, all tests were repeated except the clinical tests. One-repetition maximum torque and submaximal power and velocity (at all levels) had excellent reliability (intraclass correlation coefficient ≥ 0.943) with absolute reliability of 13.5% up to 28.3%. The agreement between days from Bland-Altman plots for power and velocity was near 0 for all levels. Hip abduction velocity had a significant positive correlation with 30CST at 60% (r = 0.416; p = 0.048) and 70% of 1RM (r = 0.442; p = 0.035). In conclusion, we showed an excellent intersession reliability of the hip abductor muscles 1RM torque and submaximal power and velocity using pneumatic resistance. Furthermore, we demonstrated that hip abduction velocity might be important for the performance of the 30CST.

Prevalence of sarcopenia in Parkinson's disease: A systematic review and meta-analysis

We meta-analysed the sarcopenia prevalence among patients with Parkinson´s disease (PD) in comparison to a control group and tested the effects of age, sex, sarcopenia assessments, and PD progression in the sarcopenia prevalence. The literature search was performed using five databases in March 2022. The prevalence of sarcopenia in patients with PD was 3 times higher than in the control group (OR 3.98). Subgroup analyses showed that among individuals aged ≥ 70 years the higher prevalence of sarcopenia in PD compared to controls (OR 5.32, P=0.08) tended to be higher (P=0.08) than the group < 70 years. Regarding PD progression, the prevalence of sarcopenia was not different between individuals scoring < 2.5 and ≥ 2.5 in the Hoehn and Yahr scale. Patients with PD have a higher probability of developing sarcopenia when compared with the control group and older PD patients trended to have even higher chance of sarcopenia than their older controls.

Objective and self-perceived lower limb weakness in Parkinson's disease

BACKGROUND

Lower limb weakness is a long-recognized symptom in patients with Parkinson's disease (PD), described by James Parkinson in his seminal report on 'paralysis agitans'. However, little is known on the frequency, clinical correlations, and association with objective decrease in muscle strength in such patients.

OBJECTIVE

The objective of this study was to assess the frequency of objective and perceived lower limb weakness in patients with PD.

METHODS

We studied 90 consecutive patients with PD and 52 age-matched controls. We recorded clinical and demographic variables, as well as perceived weakness and allied abnormal lower limb sensations, including 'heavy legs', 'fatigued legs', and 'pain'. Symptoms consistent with restless legs syndrome were not considered. Lower limb strength was determined in both legs by means of the Medical Research Council scale, dynamometric (leg flexion) and weighting machine (leg pressure) measures.

RESULTS

Weakness and allied abnormal lower limb sensations were reported in 69% of patients with PD and 21% of healthy controls. Patients with PD had decreased leg pressure compared with healthy controls (p = 0.002). Among patients with PD, an association between perceived leg weakness (and allied sensations) and gait freezing (p = 0.001) was observed in the multivariate regression analysis; however, these variables only explained 30.4% of the variance. Moreover, PD patients with and without abnormal lower limb sensations had similar muscle strength by objective measurements.

CONCLUSION

Perceived lower limb weakness and allied abnormal sensations are common in patients with PD. However, there is a dissociation between perceived weakness and objective muscle strength in the lower limbs. These abnormal sensations were mostly related to gait freezing but a causal association is questionable.

Investigation of the relationship between trunk position sense and balance, functional mobility, fear of falling, and disease stage in Parkinson's disease

INTRODUCTION

Parameters related to trunk control such as balance disorders, mobility problems, and falling are frequently observed in patients with Parkinson's disease (PD). However, to provide a stable foundation for movement, trunk stability requires appropriate adequate position sense. The aim of the study was to examine the relationship between trunk position sense, balance, functional mobility, fear of falling, and disease stage in patients with PD.

METHODS

The study was conducted in 41 patients with PD (16 female and 25 male). Trunk position sense was assessed with a digital inclinometer, balance with functional reach test, Berg balance scale and one-leg stand test, functional mobility with timed up and go test, fear of falling with activity-specific balance confidence scale, and disease stage with Modified Hoehn and Yahr Scale (MHYS). All patients were tested during the "on" phase following drug therapy.

RESULTS

Repositioning error degree was related with MHYS, Berg balance scale, right and left one-leg stand test, forward functional reach test, timed up and go test, timed up and go test-cognitive and activity-specific balance confidence scale results in patients with PD (r =  - 0.363/ - 0.609, p < 0.05 for all).

CONCLUSION

It was shown in the study that trunk position sense was associated with disease stage, balance level, functional mobility, and fear of falling in patients with PD. These results suggest that trunk position sense is more important to plan effective rehabilitation program for development and protection of disease stage, balance level, functional mobility, and fear of falling in patients with PD.

Walking function determinants in parkinson patients undergoing rehabilitation

BACKGROUND: To date little is known about factors affecting walking rehabilitation in Parkinson’s disease (PD) patients. OBJECTIVE: This prospective observational cohort study evaluated the walking distance covered in 6 minutes (6 MWD) before and after conventional rehabilitation and verified which among PD motor disorders was the most important determinant of walking distance in PD patients undergoing rehabilitation. METHODS: Data were collected from 55 PD patients, performing a conventional outpatient motor rehabilitation program. The 6MWD at the end of rehabilitation and gain in 6MWD were the outcome measures. The Unified Parkinson’s Disease Rating Scale, Hoehn and Yahr scale, Nine Hole Peg Test, Grip and Pinch test, ROM wrist motility, and Berg Balance Scale (BBS) were used to assess PD patients at admission and were considered as dependent variables. Backward multiple regression analyses identified the determinants of 6MWD outcomes. RESULTS: The 6MWD was 246.58±115 meters at admission and 286.90±116 at the end of rehabilitation. At end of rehabilitation, the 6MWD was 42.32±47 meters greater than admission (p <  0.001), corresponding to an increase of +17.16% . At the end of rehabilitation, the 6MWD was significantly longer in PD patients with stages 1–3 of the Hoehn and Yahr scale. Berg Balance Scale (β= 0.47, p <  0.001) and right Grip and Pinch at admission (β= 0.36, p = 0.001) were the only determinants of final 6MWD. The R2 value of the model was 0.47 (R2 adjusted 0.45). No variable was a determinant of gain in 6MWD. CONCLUSIONS: The study indicates that balance and generalized muscle strength are important determinants of walking rehabilitation in PD patients, in whom it is essential to maintain high levels of balance and muscle strength for a time as long as possible. These findings suggest planning more intensive rehabilitation treatments in PD patients with low levels of balance and muscle strength.

Leg Muscle Strength Correlates with Gait Performance in Advanced Parkinson Disease

Objective Leg muscle strength (LMS) is decreased in early-stage Parkinson disease (PD) patients and is associated with slower walking and falls. However, LMS in advanced PD has not been well investigated. The purpose of this study was to evaluate LMS in advanced PD patients and its effects on gait performance, activities of daily living, and the cognitive function. Methods The medical records of 132 patients with idiopathic advanced PD [Hoehn and Yahr (H&Y) stages 3 and 4] with a mean disease duration of 9.6 years were retrospectively reviewed. Leg extensor muscle strength of the patients was measured using a Strength Ergo 240. The associations between the LMS and gait performance, Barthel index, H&Y stage, and Mini-Mental State Examination (MMSE) score were analyzed. Results A Spearman's correlation analysis showed that LMS was correlated with the sex, age, age of disease onset, H&Y stage, Barthel index, MMSE score, and gait parameters. A multivariable linear regression analysis for identifying predictors of LMS showed that the gait velocity (β=0.377), Barthel index (β=0.281), sex (β=-0.187), and disease duration (β=-0.155) were significant. A receiver operating characteristic curve analysis for discriminating between H&Y stage 3 and 4 was performed for LMS; the area under the curve was 0.774 (95% confidence interval=0.696-0.851). Conclusions LMS was strongly associated with multiple domains of clinical characteristics, especially gait velocity and the Barthel index. Our study also suggested that LMS can be a predictor of PD progression.

Brain-Predicted Age Difference Moderates the Association Between Muscle Strength and Mobility

BACKGROUND

Approximately 35% of individuals over age 70 report difficulty with mobility. Muscle weakness has been demonstrated to be one contributor to mobility limitations in older adults. The purpose of this study was to examine the moderating effect of brain-predicted age difference (an index of biological brain age/health derived from structural neuroimaging) on the relationship between leg strength and mobility.

METHODS

In community dwelling older adults (N = 57, 74.7 ± 6.93 years; 68% women), we assessed the relationship between isokinetic leg extensor strength and a composite measure of mobility [mobility battery assessment (MBA)] using partial Pearson correlations and multifactorial regression modeling. Brain predicted age (BPA) was calculated from T1 MR-images using a validated machine learning Gaussian Process regression model to explore the moderating effect of BPA difference (BPAD; BPA minus chronological age).

RESULTS

Leg strength was significantly correlated with BPAD (r = -0.317, p < 0.05) and MBA score (r = 0.541, p < 0.001). Chronological age, sex, leg strength, and BPAD explained 63% of the variance in MBA performance (p < 0.001). BPAD was a significant moderator of the relationship between strength and MBA, accounting for 7.0% of MBA score variance [△R 2 = 0.044, F(1,51) = 6.83, p = 0.01]. Conditional moderation effects of BPAD indicate strength was a stronger predictor of mobility in those with a great BPAD.

CONCLUSION

The relationship between strength and mobility appears to be influenced by brain aging, with strength serving as a possible compensation for decline in neural integrity.

Boxing with and without Kicking Techniques for People with Parkinson's Disease: An Explorative Pilot Randomized Controlled Trial

BACKGROUND

People with Parkinson's disease (PD) benefit from boxing exercise. Adding kicking variations to the boxing may provide additional benefit to improve balance. However, the benefits and adherence to such trainings is unknown.

OBJECTIVE

To explore the feasibility, safety, and benefits on balance of boxing training combined with kicking techniques in comparison to boxing without kicking in PD.

METHODS

Participants were randomized to group-based boxing training with kicking techniques (BK) or to group-based boxing alone training (BO). Both groups trained for one hour, once a week, for a period of 10 weeks. Participants were assessed at baseline and ten weeks post-intervention for difference in balance, fear of falling, balance confidence, walking ability, and quality of life.

RESULTS

Twenty-nine people with PD (median age 64 years; median disease duration 5 years) participated. Both interventions were feasible and acceptable for all participants. No adverse events occurred. Most participants (BK 80%; BO 75%) were satisfied with the training. We found no significant between group difference on either the primary (Mini-BEST) or secondary outcomes. The within group comparison showed that balance improved in both groups after the intervention (BK 22.60 (2.7) to 25.33 (2.64) p = 0.02; BO 23.09 (3.44) to 25.80 (2.39); p = 0.01 on the Mini BEST test).

CONCLUSION

Both types of boxing seem to be feasible and safe. Adding kicking techniques to boxing does not improve balance significantly more than boxing alone. Incorporation of kicking may be a valuable addition to the exercise therapy repertoire.

Exercise Intolerance and Oxygen Desaturation in Patients with Parkinson's Disease: Triggers for Respiratory Rehabilitation?

The role that oxygen desaturation plays in exercise tolerance and its rehabilitative implications in patients with Parkinson's disease (PD) are unclear. We aimed to test exercise tolerance and oxygen saturation levels both during exercise and at night in PD patients to better define their rehabilitative needs. In clinically stable PD patients, undergoing inpatient rehabilitation, and in "ON" phase, we prospectively assessed clinical data, sleepiness, comorbidities, PD severity (Hoehn&Yahr, HY), motor function (ADLs, UPDRSII and UPDRSIII, Barthel Index, Functional Independence Measure), balance, spirometry, respiratory muscles (MIP/MEP), peak cough expiratory flow (PCEF), continuous night oxygen monitoring, and meters at 6MWT. Of 55 patients analyzed (28 with moderate-severe PD, HY ≥ 2.5), 37% and 23% showed moderate-severe impairment on UPDRSII and UPDRSIII, respectively; 96% had reduced exercise tolerance and severe respiratory muscles impairment (MIP/MEP < 45% pred.); 21.8% showed desaturations during exercise; and 12.7% showed nocturnal desaturations. At multiple regression, low exercise tolerance and low mean nocturnal and exercise-induced saturation correlated with several respiratory and motor function and disability indices (all p < 0.03). Exercise tolerance, exercise-induced desaturations, and nocturnal desaturations were extremely frequent in PD patients and were worse in more severe PD patients. This suggests considering a combined role for motor and respiratory rehabilitation in these patients.

Assessment of Force Production in Parkinson's Disease Subtypes

Muscle weakness is a secondary motor symptom of Parkinson's disease (PD), especially in the subtype characterized by postural instability and gait difficulty (PIGD). Since the PIGD subtype also presents worse bradykinesia, we hypothesized that it also shows a decreased rate of force development, which is linked to an increased risk of falling in PD. Therefore, we investigated the effects of PD and PD subtypes on a force production profile and correlated the force production outcomes with clinical symptoms for each PD subtype. We assessed three groups of participants: 14 healthy older adults (OA), 10 people with PD composing the PIGD group, and 14 people with PD composing the tremor-dominant group. Three knee extension maximum voluntary isometric contractions were performed in a leg extension machine equipped with a load cell to assess the force production. The outcome measures were: peak force and rate of force development (RFD) at 50 ms (RFD50), 100 ms (RFD100), and 200 ms (RFD200). We observed lower peak force, RFD50, RFD100, and RFD200 in people with PD, regardless of subtypes, compared with the OA group (p < 0.05 for all comparisons). Together, our results indicated that PD affects the capacity to produce maximal and rapid force. Therefore, future interventions should consider rehabilitation programs for people with PD based on muscle power and fast-force production, and consequently reduce the likelihood of people with PD falling from balance-related events, such as from an unsuccessful attempt to avoid a tripping hazard or a poor and slower stepping response.

The key role of physical activity against the neuromuscular deterioration in patients with Parkinson's disease

AIM

Decreased muscle strength has been frequently observed in individuals with Parkinson's disease (PD). However, this condition is still poorly examined in physically active patients. This study compared quadriceps (Q) maximal force and the contribution of central and peripheral components of force production during a maximal isometric task between physically active PD and healthy individuals. In addition, the correlation between force determinants and energy expenditure indices were investigated.

METHODS

Maximal voluntary contraction (MVC), resting twitch (RT) force, pennation angle (θp), physiological cross-sectional area (PCSA) and Q volume were assessed in 10 physically active PD and 10 healthy control (CTRL) individuals matched for age, sex and daily energy expenditure (DEE) profile.

RESULTS

No significant differences were observed between PD and CTRL in MVC (142 ± 85; 142 ± 47 N m), Q volume (1469 ± 379; 1466 ± 522 cm³ ), PCSA (206 ± 54; 205 ± 71 cm² ), θp (14 ± 7; 13 ± 3 rad) and voluntary muscle-specific torque (MVC/PCSA [67 ± 35; 66 ± 19 N m cm^-2 ]). Daily calories and MVC correlated (r = 0.56, P = .0099). However, PD displayed lower maximal voluntary activation (MVA) (85 ± 7; 95 ± 5%), rate of torque development (RTD) in the 0-0.05 (110 ± 70; 447 ± 461 N m s^-1 ) and the 0.05-0.1 s (156 ± 135; 437 ± 371 N m s^-1 ) epochs of MVCs, whereas RT normalized for PCSA was higher (35 ± 14; 20 ± 6 N m cm^-2 ).

CONCLUSION

Physically active PDs show a preserved strength of the lower limb. This resulted by increasing skeletal muscle contractility, which counterbalances neuromuscular deterioration, likely due to their moderate level of physical activity.

Evidence for Early and Regular Physical Therapy and Exercise in Parkinson's Disease

Advances in medical management of Parkinson's disease (PD) have resulted in living longer with disability. Although disability worsens over the course of the disease, there are signs of disability even in the early stages. Several studies reveal an early decline in gait and balance and a high prevalence of nonmotor signs in the prodromal period that contribute to early disability. There is a growing body of evidence revealing the benefits of physical therapy and exercise to mitigate motor and nonmotor signs while improving physical function and reducing disability. The presence of early disability coupled with the benefits of exercise suggests that physical therapy should be initiated earlier in the disease. In this review, we present the evidence revealing early disability in PD and the effectiveness of physical therapy and exercise, followed by a discussion of a secondary prevention model of rehabilitation to reduce early disability and optimize long-term outcomes.

Sarcopenia in Patients With Parkinson's Disease: A Systematic Review and Meta-Analysis

Background: Parkinson's disease (PD) and sarcopenia are two common diseases in aging people. To date, the prevalence of sarcopenia in PD patients and the relationship between clinical features and sarcopenia in PD patients are not clear. The aim of the study was to (1) assess the prevalence of sarcopenia in PD patients and (2) reveal the clinical features between PD patients with and without sarcopenia. Method: A systematic review was carried out through screening PubMed, EMBASE, and Cochrane database in May 2020. All study designs (case-control, cohort, and cross-sectional studies) were eligible for meta-analysis. Data of patients' characteristics, sarcopenia criteria, sarcopenia prevalence, and sarcopenia measures were retrieved. The primary outcome was estimated prevalence of sarcopenia by a pooled prevalence (%) and its 95% confidence interval (CI), using a random-effects model. The secondary outcome was the differences in clinical features between PD patients with and without sarcopenia by meta-analysis. Included articles were assessed for risk of bias. Potential sources of variation were investigated by using subgroup analyses and meta-regression. Result: Ten studies were included in the review. Among them, nine were cross-sectional studies, and one was a prospective cohort study. Age of participants with PD in the studies ranged from 51.1 to 80.7 years. The estimated prevalence of sarcopenia ranged from 6 to 55.5%. The random-effects pooled prevalence was 29% (95% CIs: 0.18-0.40). When only studies at low risk of bias were considered, pooled prevalence decreased to 17% (95% CIs: 0.02-0.33), with still high heterogeneity. The incidence of falls in PD patients with sarcopenia was higher than that in PD patients without sarcopenia. There was no difference in sex ratio between PD patients with and without sarcopenia. Conclusion: Sarcopenia seems to be common in patients with PD. Early assessment of sarcopenia should be implemented in PD to avoid fall and disability.

Plantarflexor strength, gait speed, and step length change in individuals with Parkinson's disease

Parkinson's disease affects the ability to walk often resulting in decreased independence and low quality of life. The purpose of this study was to examine differences in plantarflexor strength (PFS), gait speed, and step length in persons with Parkinson's disease (PwP) and healthy peers using clinical measures. A secondary purpose was to examine the relationship between these gait components across disease severity. The study was a convenience sample of 71 PwP and 25 community healthy peers. Outcome measures included 10-Meter Walk, step length, and Calf-Raise Senior Test. PwP were separated into mild and moderate impairment groups using the Movement Disorders Society United Parkinson's Disease Rating Scale Motor Subscale. Between group differences for gait speed (F2,93 = 24.560, P = 0.000), step length (F2,93 = 21.93, P = 0.000) and PFS (F2,93 = 19.49, P < 0.000) were observed. Post hoc testing determined a difference (P < 0.00) in gait speed, step length, and PFS testing between moderate impairment versus healthy peers and mild impairment. A difference (P = 0.045) in step length and a trend towards significance (P = 0.064) for PFS was found between healthy peers and mild impairment group. This study revealed that PwP with mild impairment also have significant changes in step length and trends toward plantarflexor weakness without a significant difference in gait speed. These early changes may warrant early assessment and intervention to prevent decline. This study may bring clinical focus onto the plantarflexor and step length for early comprehensive assessment and treatment of gait and mobility for PwP.

Associations between functional fitness and walking speed in older adults

This cross-sectional study aimed to explore 1) the overall associations between functional fitness and walking speed in older adults and 2) the key functional fitness parameters affecting older adults' walking speeds. A total of 242 apparently healthy older adults finished a 6-m walking speed test at both usual walking speed (UWS) and maximum walking speed (MWS). Functional fitness was assessed using the Senior Fitness Test battery. The results revealed significantly moderate correlations of functional fitness with UWS (r = 0.380) and MWS (r = 0.436). Both age (UWS = -0.332, MWS = -0.324) and dynamic balance and agility (UWS = 0.329, MWS = 0.411) were key indicators of both UWS and MWS. In addition, gender (r = 0.090), aerobic endurance (r = 0.326), and lower body flexibility (r = 0.183) were key fitness indicators of MWS in older adults.

Health-Related Quality of Life and Physical Function in Individuals with Parkinson's Disease after a Multidisciplinary Rehabilitation Regimen-A Prospective Cohort Feasibility Study

Parkinson’s disease (PD) is a neurodegenerative disease and a multidisciplinary approach to rehabilitation has been suggested as the best clinical practice. However, very few studies have investigated the long-term effects of a multidisciplinary rehabilitation approach, particularly regarding whether this can slow the progression of PD. The purpose was to investigate the short- and long-term effect of a 2-week multidisciplinary rehabilitation regimen on the PD-related decline in health-related quality of life (HRQOL), mobility, and muscle function. Individuals with PD (IPD) participated in a 2-week inpatient multidisciplinary rehabilitation regimen that focused on improving HRQOL, mobility, and muscle function. Data from the primary outcome: HRQOL (Parkinson’s Disease Questionnaire 39, PDQ-39), secondary outcomes: handgrip strength, Timed-up and Go (TUG), Hospital Anxiety and Depression Scale (HADS), and Falls Efficacy Scale-International (FES-I) were compared at pre-visitation, before and after the 2-week regimen, and again at 4 and 10 months follow-up. In total, 224 patients with PD were included. There were short-term improvements in all outcomes. PDQ-39 was maintained at the same level as pre-visitation after 10 months follow-up. A 2-week multidisciplinary rehabilitation regimen improved short-term mobility, muscle function, and HRQOL in individuals with Parkinson’s disease. HRQOL was maintained after 10 months demonstrating long-term effects.

Effects of a power strength training using elastic resistance exercises on the motor and non-motor symptoms in patients with Parkinson's disease H&Y 1-3: study protocol for a randomised controlled trial (PARK-BAND Study)

INTRODUCTION

Parkinson's disease (PD) is the second most common neurodegenerative disorder in Brazil. Physical activity is a complementary intervention in managing inherent declines associated with the disease like strength, balance, gait, and functionality and benefit health-related outcomes. Here, we report the PARK-BAND Study protocol, which aims to investigate potential benefits of power training using elastic devices in participants with PD. Our intervention will be provided in patients with PD using elastic devices like elastic bands and tubes. Therefore, we used the term Park from Parkinson's disease and band from elastic bands.

METHODS AND ANALYSIS

This randomised single-blind single-centre two-arm parallel, superiority trial will include 50 participants with PD attending the clinical setting. Those who meet the eligibility criteria and provide consent to participate will be randomised in a 1:1 ratio to either the exercise group, which will receive power training programme or the health education group, which will receive the education programme. Randomisation will be performed by permuted block randomisation with a block size of eight. Both groups will receive a 12-week intervention. The exercise group will have two sessions per week and the health education group will have one session per week. Changes from baseline in bradykinesia, as assessed by the Unified Parkinson's Disease Rating Scale motor examination subscore and physical functional performance, will be the primary outcomes. Secondary outcomes include other neurological, neurophysiological and physical variables, as well as the quality of life, depression, cognition, sleep quality and disturbances, assessed before and after interventions. We hypothesise that the exercise group will have greater improvement in primary and secondary outcomes than the health education group.

ETHICS AND DISSEMINATION

The study is approved by the Research Ethics Committee of Hospital Universitário Walter Cantidio and all participants will provide their written informed consent (register number 91075318.1.0000.5045).Trial results will be disseminated via peer reviewed journal articles and conference presentations, reports for organisations involved with PD and for participants.

TRIAL REGISTRATION NUMBER

Registro Brasileiro de Ensaios Clínicos Registry (RBR-5w2sqt); Pre-results.

Maximal strength training in patients with Parkinson's disease: impact on efferent neural drive, force-generating capacity, and functional performance

Parkinson's disease (PD) is characterized by progressive neurological deterioration, typically accompanied by reductions in skeletal muscle force-generating capacity (FGC) and functional performance. Physical activity has the potential to counteract this debilitating outcome, however, it is elusive if high-intensity strength training included in conventional treatment may improve results. Therefore, we randomly assigned 22 PD patients (74 ± 9 yr) to conventional rehabilitation with or without maximal strength training (MST) performed as leg press and chest press at ~90% of one repetition maximum (1RM), five times per week for 4 wk. FGC, physical performance, and efferent neural drive assessed as evoked potentials (V-wave normalized to M-wave in m. soleus) were measured following training. Results revealed that only MST improved 1RM leg press (101 ± 23 to 118 ± 18 kg) and chest press (36 ± 15 to 41 ± 15 kg), plantar flexion maximal voluntary contraction (235 ± 125 to 293 ± 158 N·m), and rate of force development (373 ± 345 to 495 ± 446 N·m·s^-1; all P < 0.05; different from controls P < 0.05). FGC improvements were accompanied by an increased efferent neural drive to maximally contracting musculature (V-to-M ratio: 0.17 ± 0.12 to 0.24 ± 0.15; P < 0.05; different from controls P < 0.05), improved physical performance (stair climbing: 21.0 ± 9.2 to 14.4 ± 5.2 s; timed up and go: 7.8 ± 3.3 to 6.2 ± 2.5 s; both P < 0.05), and self-perceived improvement in health (3.1 ± 0.5 to 2.6 ± 0.9) and social activities functioning (2.2 ± 1.0 to 1.5 ± 1.1; both P < 0.05). No changes were observed in the control group. In conclusion, this study shows that MST improves FGC, neuromuscular function, and functional performance and advocates that high-intensity strength training should be implemented as an adjunct therapy in the treatment of PD patients.NEW & NOTEWORTHY This randomized, controlled trial documents that supervised high-intensity strength training improves efferent neural drive, maximal muscle strength, rate of force development, and functional performance in patients with Parkinson's disease (PD). In contrast, no differences were observed in these outcome variables in patients receiving conventional treatment consisting of recreational physical activity with low-to-medium intensity. Consequently, this study advocates that high-intensity strength training should be implemented in the clinical treatment of PD patients.

Gait characteristics in individuals with Parkinson's disease during 1-minute treadmill walking

Background

No previous study has examined the age-dependent characteristics of gait in individuals between 50 and 79 years simultaneously in healthy individuals and individuals with Parkinson’s disease (PD) over continuous gait cycles. This study aimed to investigate age-related differences in gait characteristics on individuals age ranged 50–79 years, including individuals with PD, during a 1-minute treadmill walking session. Additionally, we aimed to investigate the differences associated with spatiotemporal gait parameters and PD compared in age-matched individuals.

Methods

This study included 26 individuals with PD and 90 participants age ranged 50–79 years. The treadmill walking test at a self-preferred speed was performed for 1 min. The embedded inertial measurement unit sensor in the left and right outsoles-based system was used to collect gait characteristics based on tri-axial acceleration and tri-axial angular velocities.

Results

Participants aged >60 years had a decreased gait speed and shortened stride and step, which may demonstrate a distinct shift in aging (all p < 0.005). Individuals with PD showed more of a decrease in variables with a loss of consistency, including gait asymmetry (GA), phase coordination index (PCI) and coefficient of variation (CV) of all variables, than age-matched individuals (all p < 0.001). Gait speed, stride and step length, stance phase, variability, GA and PCI were the variables that highly depended on age and PD.

Discussion

Older adults could be considered those older than 60 years of age when gait alterations begin, such as a decreased gait speed as well as shortened stride and step length. On the other hand, a loss of consistency in spatiotemporal parameters and a higher GA and PCI could be used to identify individuals with PD. Thus, the CV of all spatiotemporal parameters, GA and PCI during walking could play an important role and be useful in identifying individuals with PD.

Conclusion

This study provided the notable aging pattern characteristics of gait in individuals >50 years, including individuals with PD. Increasing age after 60 years is associated with deterioration in spatiotemporal parameters of gait during continuous 1-minute treadmill walking. Additionally, GA, PCI and the CV of all variables could be used to identify PD which would be placed after 70 years of age. It may be useful to determine the decline of gait performance in general and among individuals with PD.

Mechanism of Fatigue Induced by Different Cycling Paradigms With Equivalent Dosage

Leg cycling is one of the most common modes of exercise used in athletics and rehabilitation. This study used a novel cycling setting to elucidate the mechanisms, central vs. peripheral fatigue induced by different resistance with equivalent works (watt∗min). Twelve male adults received low and relatively high resistance cycling fatigue tests until exhausted (RPE > 18) in 2 weeks. The maximal voluntary contraction, voluntary activation level, and twitch forces were measured immediately before and after cycling to calculate General (GFI), central (CFI), and peripheral (PFI) fatigue indices of knee extensors, respectively. The results showed that the CFI (high: 92.26 ± 8.67%, low: 78.32 ± 11.77%, p = 0.004) and PFI (high: 73.76 ± 17.32%, low: 89.63 ± 11.01%, p < 0.017) were specific to the resistance of fatigue protocol. The GFI is influenced by the resistance of cycling to support the equivalent dosage. This study concluded that the mechanism of fatigue would be influenced by the resistance of fatigue protocol although the total works had been controlled.

Clinical correlates of sarcopenia and falls in Parkinson's disease

BACKGROUND

Sarcopenia is a complex and multifactorial geriatric condition seen in several chronic degenerative diseases. This study aimed to screen for sarcopenia and fall risk in a sample of Parkinson's disease (PD) patients and to investigate demographic and clinical factors associated.

METHODS

This is a cross-sectional study. We evaluated 218 PD patients at the Movement Disorders Clinic in Fortaleza, Brazil, and collected clinical data including experiencing falls in the six months prior to their medical visit. Probable sarcopenia diagnosis was confirmed by using a sarcopenia screening tool (SARC-F questionnaire) and the presence of low muscle strength.

RESULTS

One hundred and twenty-one patients (55.5%) were screened positive for sarcopenia using the SARC-F and 103 (47.4%) met the criteria for probable sarcopenia. Disease duration, modified Hoehn and Yahr stage, Schwab and England Activities of Daily Living Scale score, levodopa equivalent dose, probable sarcopenia and positive SARC-F screening were all associated with experiencing falls. Disease duration, lower quality of life and female gender were independently associated with sarcopenia. Experiencing falls was significantly more frequent among patients screened positive in the SARC-F compared to those screened negative.

CONCLUSIONS

Sarcopenia and PD share common pathways and may affect each other's prognosis and patients' quality of life. Since sarcopenia is associated with lower quality of life and increased risk of falls, active case finding, diagnosis and proper management of sarcopenia in PD patients is essential.

Executive Functioning, Muscle Power and Reactive Balance Are Major Contributors to Gait Adaptability in People With Parkinson's Disease

Background and Aim: The ability to adapt gait when negotiating unexpected hazards is crucial to maintain stability and avoid falling. This study investigated cognitive, physical and psychological factors associated with gait adaptability required for obstacle and stepping target negotiation in people with Parkinson’s disease (PD).

Methods: Fifty-four people with PD were instructed to either: (a) avoid an obstacle at usual step distance; or (b) step onto a target at either a short or long step distance projected on a walkway two heel strikes ahead and then continue walking. Participants also completed clinical [Hoehn & Yahr rating scale; Movement Disorders Society version of the Unified Parkinson’s Disease Rating Scale motor section (MDS-UPDRS-III)], cognitive [simple reaction time, Trail Making and Stroop stepping (difference between incongruent and standard Choice Stepping Reaction Time, CSRT) tests], physical [hip abductor muscle power and reactive balance (pull test from the MDS-UPDRS-III)] and psychological (Fall Efficacy Scale–International) assessments.

Results: Discriminant function analysis revealed Stroop stepping test (inhibitory control) performance was the best predictor of stepping errors across the Gait Adaptability Test (GAT) conditions. Poorer executive function [Trail Making Test (TMT)] and reactive balance predicted poorer stepping accuracy in the short target condition; poorer reactive balance predicted increased number of steps taken to approach the obstacle and the long target; and poorer executive function predicted obstacle avoidance. Weaker hip abductor muscle power, poorer reactive balance, slower reaction time, poorer executive function and higher concern about falling were significant predictors of shorter step length while negotiating the obstacle/targets.

Conclusion: Superior executive function, effective reactive balance and good muscle power were associated with successful gait adaptability. Executive function and reactive balance appear particularly important for precise foot placements; and cognitive capacity for step length adjustments for avoiding obstacles. These findings suggest that impaired inhibitory control contributes to stepping errors and may increase fall risk in people with PD. These findings help elucidate mechanisms for why people with PD fall and may facilitate fall risk assessments and fall prevention strategies for this group.

Assessment of the impact of an exercise program on the physical and functional capacity in patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay: An exploratory study

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a neuromuscular disorder caused by the mutation of the SACS gene. Clinical symptoms of this disease include progressive ataxia, spasticity, and peripheral neuropathy. Similar to other neuromuscular disorders, these patients are prone to physical deconditioning which may lead to a loss of functional capacity. This paper aims to evaluate the impact of a training program on the physical fitness and the functional capacity of ARSACS patients. Twelve patients (age: 28.1 ± 8.2 years) participated in this study. They followed an eight-week training program including physical activities, strength-power and aerobic training. Compared to the initial evaluation, measures of physical fitness and functional capacity were significantly improved (p ≤ 0.05) for 11 of the 12 tests. Positive gains were also observed for fall frequency and for upper-limb incoordination. This paper supports the importance of a training program for ARSACS patients in order to improve their quality of life. Through these types of interventions, it may be possible to slow down the progression of the disease and help maintain functional capacity.

A Novel Method to Determine Optimal Load in Elastic-Based Power Training

Buskard, AN, Oh, J, Eltoukhy, M, Brounstein, SR, and Signorile, JF. A novel method to determine optimal load in elastic-based power training. J Strength Cond Res 32(9): 2401-2408, 2018-The benefits of muscular power on sport performance and older adults' abilities to live independently and resist falls is well documented. Consequently, a substantial volume of research has focused on establishing the optimal loading patterns for improving muscular power using resistance exercise; however, to date, this research has only targeted optimal loading during training with free weights or selectorized exercise machines. Conversely, no approach has been developed to establish optimal loads for elastic modalities, such as tubes and bands, commonly used for sports rehabilitation, injury prevention, and training older adults. Therefore, the purpose of this study was to evaluate a new method for determining the optimal tubes to use in power training performed with elastic resistance. Thirty-eight recreationally active college students (age, 23.7 ± 4.5 years) were recruited to perform 3 single-arm bicep curls at a maximum intended velocity using 6 elastic tubes of varying resistance. Testing was performed in a 3-dimensional (3D) motion analysis laboratory using a specially constructed platform with an integrated strain gauge to which each tube was anchored. Force data from the strain gauge and velocity data from the 3D motion capture system were then used to compute power for each tube. An analysis based on individual's cable arm curl 1-repetition maximum (1RM) was then used to generate general guidelines for the most appropriate tube to use for arm curl power training based on upper arm 1RM. Our results demonstrate the feasibility of using this methodology for other exercises, thereby establishing optimal tube use for power training based on each exercise's 1RM.

WITHDRAWN: Assessment of the impact of an exercise program on the physical and functional capacity in patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay: An exploratory study

Ahead of Print article withdrawn by publisher. This withdrawal is for above article due to the misoperation of advance online publication.

High-Speed Resistance Training Modifies Load-Velocity and Load-Power Relationships in Parkinson's Disease

Muscle power is a major neuromuscular factor affecting motor function and independence in patients with Parkinson's disease (PD), and it is commonly targeted using high-speed exercise. This study examined the changes in velocities (Vpp) and percent loads (%1RMpp) at peak power and load-velocity (L-V) and load-power (L-P) relationships, resulting from resistance training because of exercise choice and loading in older patients with PD. Fourteen older adults with mild to moderate PD participated in a 12-week randomized controlled power training trial. Changes in L-V and L-P relationships for the biceps curl, chest press, leg press, hip abduction, and seated calf were assessed using pneumatic resistance machines at loads ranging from 30 through 90% of subjects' 1 repetition maximum for each exercise. Significant increases in Vpp were seen for biceps curl, leg press, hip abduction, and seated calf and decreases in %1RMpp were noted for biceps curl and hip abduction. Additionally, unique patterns of change were seen in these relationships across exercises, with biceps curl, chest press, and leg press showing the greatest shifts at the lower load end of the loading spectrum, and hip abduction and seated calf showing greatest responses at the higher end. The patterns of change in L-V and L-P relationships provide evidence for the unique responses of the specific muscle groups and joints to the exercises evaluated and offer a framework for more exacting exercise prescriptions in patients with PD.

Prática mental após fisioterapia mantém mobilidade funcional de pessoas com doença de Parkinson

RESUMO O objetivo deste estudo foi avaliar a prática mental após a fisioterapia motora para manutenção dos efeitos obtidos na mobilidade funcional de pessoas com doença de Parkinson (DP). Este ensaio clínico randomizado controlado, com cegamento simples, incluiu 14 sujeitos com DP nos estágios de 1 a 3 (escala de Hoehn & Yahr), com idade entre 45 e 72 anos. Após a avaliação inicial com o Timed Up & Go (TUG), Dynamic Gait Index (DGI) e Falls Efficacy Scale - International Brazil (FES-I Brasil), os sujeitos realizaram 15 sessões de fisioterapia motora. Foram reavaliados e divididos randomicamente em Grupo Controle (GC) e Grupo Prática Mental (GPM). Após a alocação, o GPM foi submetido a 10 sessões de prática mental associada a orientações de exercícios domiciliares. O GC foi orientado apenas a realizar os exercícios domiciliares. Em seguida, os grupos foram novamente reavaliados. Verificou-se que o GPM continuou apresentando redução na média de tempo do TUG na segunda reavaliação (p=0,05). Na segunda reavaliação do DGI, o GPM manteve a mesma média de escore da primeira reavaliação e o GC apresentou declínio da média. Não foram verificadas diferenças significativas na comparação intergrupos dos escores na FES-I Brasil. A prática mental foi capaz de manter os ganhos obtidos pela fisioterapia na mobilidade funcional de pacientes com DP.

Amount, Distribution, and Quality of Protein Intake Are Not Associated with Muscle Mass, Strength, and Power in Healthy Older Adults without Functional Limitations-An enable Study

To maintain muscle mass in older age, several aspects regarding the amount and distribution of protein intake have been suggested. Our objective was to investigate single and combined associations of daily protein intake, evenness of protein distribution across the three main meals, number of meals providing ≥0.4 g protein/kg body weight (BW), and number of meals providing ≥2.5 g leucine, with muscle mass, strength, and power in successful agers. In this cross-sectional study in 97 healthy community-dwelling adults without functional limitations aged 75-85 years, protein intake was assessed using 7-day food records. Muscle mass, leg muscle strength, leg muscle power, and handgrip strength were measured according to standardized protocols. Mean daily protein intake was 0.97 ± 0.28 g/kg BW and the coefficient of variance between main meals was 0.53 ± 0.19. Per day, 0.72 ± 0.50 meals providing ≥0.4 g protein/kg BW and 1.11 ± 0.76 meals providing ≥2.5 g leucine were consumed. No correlations between single or combined aspects of protein intake and skeletal muscle index, leg muscle power, leg muscle strength, or handgrip strength were observed (Spearman's r of -0.280 to 0.291). In this sample of healthy older adults without functional limitations, aspects of protein intake were not associated with muscle mass, strength, or power.

Knee Extensor Rate of Torque Development Before and After Arthroscopic Partial Meniscectomy, With Analysis of Neuromuscular Mechanisms

Study Design Descriptive, prospective single-cohort longitudinal study. Background Though rapid torque development is essential in activities of daily living and sports, it hasn't been specifically tested by most physical therapists or incorporated into rehabilitation programs until late in the treatment process. Little evidence is available on quadriceps torque development capacity before and after arthroscopic knee surgery. Objectives To study knee extensor rate of torque development, contributing mechanisms, and associations with strength and patient-reported outcomes before and during the first 6 weeks after arthroscopic partial meniscectomy. Methods Twenty subjects (mean ± SD age, 42.3 ± 13.7 years; body mass index, 26.6 ± 3.1 kg/m²) were tested before surgery, and at 2 and 5 weeks after surgery. Quadriceps muscle volume, strength, activation, rate of torque development, and patient-reported outcomes were evaluated across the study period. Results Significant side-to-side differences in quadriceps strength and voluntary rate of torque development were observed at each time point (P<.05). Changes in muscle activity were associated with changes in rapid torque development capacity. Side-to-side rate of torque development deficits after surgery were associated with lower patient-reported outcomes scores. Conclusion Diminished rapid torque development capacity is common in arthroscopic meniscal debridement patients. This reduced capacity is associated with an inability to quickly recruit and drive the quadriceps muscles (neural mechanisms) and not muscle atrophy or other peripheral factors tested. Patient-reported outcomes are associated with quadriceps rate of torque development, but not strength or muscle size. Rapid torque development warrants greater attention in rehabilitation. J Orthop Sports Phys Ther 2017;47(12):945-956. Epub 9 Oct 2017. doi:10.2519/jospt.2017.7310.

Effects of 2 Years of Exercise on Gait Impairment in People With Parkinson Disease: The PRET-PD Randomized Trial

BACKGROUND AND PURPOSE

This study presents a secondary analysis from the Progressive Resistance Exercise Training in Parkinson Disease (PRET-PD) trial investigating the effects of progressive resistance exercise (PRE) and a Parkinson disease (PD)-specific multimodal exercise program, modified Fitness Counts (mFC), on spatial, temporal, and stability-related gait impairments in people with PD.

METHODS

Forty-eight people with PD were randomized to participate in PRE or mFC 2 times a week for 24 months; 38 completed the study. Gait velocity, stride length, cadence, and double-support time were measured under 4 walking conditions (off-/on-medication, comfortable/fast speed). Ankle strength was also measured off- and on-medication. Twenty-four healthy controls provided comparison data at one time point.

RESULTS

At 24 months, there were no significant differences between exercise groups. Both groups improved fast gait velocity off-medication, cadence in all conditions, and plantarflexion strength off-/on-medication. Both groups with PD had more gait measures that approximated the healthy controls at 24 months than at baseline. Plantarflexion strength was significantly associated with gait velocity and stride length in people with PD at baseline and 24 months, but changes in strength were not associated with changes in gait.

DISCUSSION AND CONCLUSIONS

Twenty-four months of PRE and mFC were associated with improved off-medication fast gait velocity and improved cadence in all conditions, which is important because temporal gait measures can be resistant to medications. Spatial and stability-related measures were resistant to long-term improvements, but did not decline over 24 months. Strength gains did not appear to transfer to gait.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A161).

A Tandem Cycling Program: Feasibility and Physical Performance Outcomes in People With Parkinson Disease

BACKGROUND AND PURPOSE

Individuals with Parkinson disease (PD) have motor and nonmotor impairments that interfere with exercise participation. The purpose of this study was to examine the feasibility and physical performance outcomes of a community-based indoor tandem cycling program that was designed to facilitate a higher cadence, consistency, and intensity of training.

METHODS

Forty-one participants with mild to moderate PD were enrolled. A high-cadence cycling protocol using mechanically augmented (or forced) exercise on a tandem bicycle was adapted for our program. Participants cycled 3 times per week for 10 weeks. Feasibility measures included program retention, attendance, and adverse events, as well as the ability to reach training goals for heart rate (HR) and cadence. Physical performance outcomes included the Berg Balance Scale (BBS), Short Physical Performance Battery (SPPB), Five-Times-Sit-to-Stand (FTSTS) Test, Timed Up and Go (TUG), and gait parameters during usual and fast-paced walking.

RESULTS

Program feasibility was demonstrated with a high attendance rate (96%) and retention rate (100%). There were no adverse events. The majority of participants reached their exercise training goals for target HR (87%) and cadence (95%). Statistically significant physical performance improvement (P < 0.05) was observed across domains of gait, balance, and mobility, suggesting a slowing or reversal of functional decline as a result of this cycling program.

DISCUSSION AND CONCLUSION

Program feasibility and improved physical performance outcomes were demonstrated in individuals with mild to moderate PD participating in a community-based indoor tandem cycling program.Video Abstract available for more insights from the authors (see supplemental digital content 1, http://links.lww.com/JNPT/A146).

Neuromuscular rate of force development deficit in Parkinson disease

BACKGROUND

Bradykinesia and reduced neuromuscular force exist in Parkinson disease. The interpolated twitch technique has been used to evaluate central versus peripheral manifestations of neuromuscular strength in healthy, aging, and athletic populations, as well as moderate to advanced Parkinson disease, but this method has not been used in mild Parkinson disease. This study aimed to evaluate quadriceps femoris rate of force development and quantify potential central and peripheral activation deficits in individuals with Parkinson disease.

METHODS

Nine persons with mild Parkinson Disease (Hoehn & Yahr≤2, Unified Parkinson Disease Rating Scale total score=mean 19.1 (SD 5.0)) and eight age-matched controls were recruited in a cross-sectional investigation. Quadriceps femoris voluntary and stimulated maximal force and rate of force development were evaluated using the interpolated twitch technique.

FINDINGS

Thirteen participants satisfactorily completed the protocol. Individuals with early Parkinson disease (n=7) had significantly slower voluntary rate of force development (p=0.008; d=1.97) and rate of force development ratio (p=0.004; d=2.18) than controls (n=6). No significant differences were found between groups for all other variables.

INTERPRETATIONS

Persons with mild-to-moderate Parkinson disease display disparities in rate of force development, even without deficits in maximal force. The inability to produce force at a rate comparable to controls is likely a downstream effect of central dysfunction of the motor pathway in Parkinson disease.

Fatigue and Muscle Strength Involving Walking Speed in Parkinson's Disease: Insights for Developing Rehabilitation Strategy for PD

Background. Problems with gait in Parkinson's disease (PD) are a challenge in neurorehabilitation, partly because the mechanisms causing the walking disability are unclear. Weakness and fatigue, which may significantly influence gait, are commonly reported by patients with PD. Hence, the aim of this study was to investigate the association between weakness and fatigue and walking ability in patients with PD. Methods. We recruited 25 patients with idiopathic PD and 25 age-matched healthy adults. The maximum voluntary contraction (MVC), twitch force, and voluntary activation levels were measured before and after a knee fatigue exercise. General fatigue, central fatigue, and peripheral fatigue were quantified by exercise-induced changes in MVC, twitch force, and activation level. In addition, subjective fatigue was measured using the Multidimensional Fatigue Inventory (MFI) and Fatigue Severity Scale (FSS). Results. The patients with PD had lower activation levels, more central fatigue, and more subjective fatigue than the healthy controls. There were no significant differences in twitch force or peripheral fatigue index between the two groups. The reduction in walking speed was related to the loss of peripheral strength and PD itself. Conclusion. Fatigue and weakness of central origin were related to PD, while peripheral strength was important for walking ability. The results suggest that rehabilitation programs for PD should focus on improving both central and peripheral components of force.