Leg-extension strength and chair-rise performance in elderly women 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.

Bilateral Force Deficit in Proximal Effectors Versus Distal Effectors in Lower Extremities

Purpose: Bilateral force deficit occurs when the maximal generated force during simultaneous bilateral muscle contractions is lower than the sum of forces generated unilaterally. Neural inhibition is stated as the main source for bilateral force deficit. Based on differences in bilateral neural organization, there might be a pronounced neural inhibition for proximal compared to distal effectors. The aim of the present experiment was to evaluate potential differences in bilateral force deficit in proximal compared to distal effectors in lower extremities. Methods: Fifteen young adults performed single-joint maximal voluntary contractions in isometric dorsiflexion of ankle (distal) and knee (proximal) extension unilaterally and bilaterally. Results: Results showed a significant absolute bilateral force deficit for both proximal (123.46 ± 59.51 N) and distal effectors (33.00 ± 35.60 N). Interestingly, the relative bilateral force deficit for knee extension was significantly larger compared to dorsiflexion of ankle, 19.98 ± 10.04% and 10.27 ± 9.57%, respectively. Our results indicate a significantly higher bilateral force deficit for proximal effectors compared to distal effectors. Conclusion: Plausible explanations are related to neuroanatomical and neurophysiological differences between proximal effectors and distal effectors where proximal muscles have a higher potential for bilateral communication compared to distal muscles. In addition, higher forces produced with proximal effectors could cause a higher perceived exertion and cause a more pronounced bilateral force deficit to proximal effectors.

Muscle Strength and Power in People With Parkinson Disease: A Systematic Review and Meta-analysis

BACKGROUND AND PURPOSE

No studies have synthesized the literature regarding mechanical muscle function (ie, strength, power, rate of force development [RFD]) in people with Parkinson disease (PD). Here, we aimed to expand our understanding of mechanical muscle function in people with PD (PwPD) by systematically reviewing (1) the psychometric properties of isokinetic/isometric dynamometry in PD, (2) the literature comparing mechanical muscle function in PwPD with healthy controls (HC), and (3) reported associations between muscle mechanical muscle function and functional capacity and/or disease severity.

METHODS

Systematic literature search in 6 databases. Included studies had to (1) enroll and report data on PwPD, (2) include assessment(s) of psychometric properties (ie, validity, reliability, responsiveness) of isokinetic/isometric dynamometry in PD, and/or (3) assess mechanical muscle function in both PwPD and HC using isokinetic/isometric dynamometry.

RESULTS

A total of 40 studies were included. Aim 1 studies (n = 2) showed high reliability for isometric dynamometry (hip-abductor/dorsiflexor/trunk flexor-extensor/handgrip: intraclass correlations coefficients range = 0.92-0.98). Aim 2 studies (n = 40) showed impaired mechanical muscle function (ie, strength, power, RFD) in PwPD compared with HC (effect sizes range = 0.52-1.89). Aim 3 studies (n = 11) showed weak-to-strong associations between overall and lower extremities muscle strength and functional capacity and/or disease severity outcomes (ie, Unified Parkinson Disease Rating Scale).

DISCUSSION AND CONCLUSIONS

Sparse methodological evidence suggests high reliability when using dynamometry in PwPD. Muscle strength, power, and RFD are impaired in PwPD compared with HC. Muscle strength is associated with functional capacity and disease severity.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A403 ).

People with mild Parkinson's disease have impaired force production in upper limb muscles: A cross-sectional study

BACKGROUND

There has been little examination of force production of the upper limb in people with Parkinson's disease (PD), despite its impact on activities of daily living and clear evidence that force production is significantly reduced in lower limb muscle groups. The aim of this study was to determine the force production of the major muscle groups of the upper limb in people with PD during the "on" phase after medication, compared with aged-matched neurologically-normal controls.

METHOD

A cross-sectional study was carried out.

PARTICIPANTS

Thirty people with mild PD (Hoehn Yahr mean 1.1) and 24 age-matched neurologically-normal controls.

OUTCOME MEASURES

Maximum isometric force production of the shoulder flexors, extensors, abductors, adductors, internal rotators and external rotators, elbow flexors and extensors, wrist flexors and extensors and hand grip using dynamometry.

RESULTS

There was a significant impairment in force production in all upper limb muscle groups, compared with control participants, except in the wrist flexors. On average the deficit in force production was 22%, despite people with PD having mild disease, being physically active and being measured during the "on" phase of medication. The most severely affected muscle groups were the upper limb extensors.

CONCLUSION

People with PD have a significant deficit in force production of the upper limb muscle groups compared with age-matched neurologically normal controls.

CLINICAL IMPLICATIONS

Regular assessment of strength of the upper limb should be considered by clinicians and strengthening interventions could be implemented if a deficit is identified.

Clinical features contributing to the sit-to-stand transfer in people with Parkinson’s disease: a systematic review

Introduction

The aim of this systematic review is to present the existing literature on the clinical motor, and non-motor factors contributing to sit-to-stand transfer in individuals with Parkinson's disease.

Data synthesis

Five databases (PubMed, PEDro, Cochrane, SCOPUS, and Ovid) were searched for literature on the contributing factors to sit-to-stand performance in Parkinson's disease. A quality check of these observational studies was done using the 'strengthening the reporting of observational studies in epidemiology' (STROBE) statement and the tool of the 'National Heart, Lung, and Blood Institute' (NHLBI). Descriptive and quantitative data were extracted and compiled, and a meta-analysis was performed to compute the standardised mean difference.

Results

Thirteen studies were selected; a majority of them provided a high-to-moderate level of evidence. Ten were cross-sectional, while the other three were case–control studies. Collectively, individuals with Parkinson's disease had a prolonged transfer time than those of age-matched healthy peers, particularly from peak horizontal velocity phase to seat-off phase, implying bradykinesia. A reduction in peak and rate to peak joint torques was also related to the decreased pace and stability of the sit-to-stand movement in individuals with Parkinson's disease. Additionally, they demonstrated exaggerated trunk flexion as a postural stabilisation strategy, allowing them to maintain and manoeuvre the relative positions of their centre of mass through the transitional phase of the transfer.

Conclusion

As per the existing literature, an alteration in strength, overall body bradykinesia, balance, posture, as well as cognition may result in an impaired sit-to-stand transfer in individuals with Parkinson's disease.

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.

Lower extremity joints and their contributions to whole limb extension

Lower extremity multi-joint strength curves tend not to evaluate individual joint contributions to endpoint force in maximum effort isometric whole limb extension. Therefore, the purpose of this study was to measure the contribution of the hip, knee, and ankle to vertical ground reaction force in maximum effort isometric whole limb extension at various postures. An effect of posture on the contributions of the hip, knee, and ankle to vertical ground reaction force was found (F_(3,96) = 85.31, p < 0.0001; F_(3,96) = 21.32, p < 0.0001; F_(3,96) = 130.61, p < 0.0001 for the hip, knee, and ankle, respectively). The hip and knee contributed most to vertical endpoint force when the lower limb was in a flexed posture, and their contributions decreased when posture was extended. Conversely, the ankle contributed least when the limb was flexed, but its contribution increased as posture was changed from flexed to more extended. In comparison to recent research involving induced acceleration analysis, it appears that the hip, knee, and ankle utilize the same force allocation strategy in multi-joint maximum effort isometric leg extensions and activities of daily living.

People with mild PD have impaired force production in all lower limb muscle groups: A cross-sectional study

BACKGROUND

Power is reduced in people with Parkinson's disease as a consequence of bradykinesia, but it is not clear whether reduced power is also due to a deficit in force production. The aim of this study was to quantify force production in all major lower limb muscle groups in people with PD during the "on" phase after medication, compared with aged-matched neurologically normal control participants.

METHOD

Design: A cross-sectional study was undertaken.

PARTICIPANTS

Thirty ambulatory people with PD and 24 neurologically normal controls.

OUTCOME MEASURES

Isometric force production of the hip flexors and extensors, hip adductors and abductors, hip internal rotators and external rotators, knee flexors and extensors, ankle dorsiflexors and plantarflexors, ankle invertors and evertors using hand-held dynamometry.

RESULTS

There was a significant deficit in force production in participants with PD in all lower limb muscle groups tested, compared with control participants. On average, force production of participants with PD was 78% (range 67%-87%) of control participants, despite participants with PD regularly participating in exercise, being measured during their "on" phase after medication and having normal walking ability. The most severely affected muscle groups were the hip adductors (67%) and ankle plantarflexors (68%).

CONCLUSION

People with PD have a significant loss of force production in all lower limb muscle groups compared with age-matched neurologically-normal controls.

IMPLICATIONS FOR PHYSIOTHERAPY PRACTICE

Clinicians should regularly assess the strength of all lower limb muscle groups, regardless of participation in physical activity, responsiveness to levodopa medication and walking ability.

Functional relevance of resistance training-induced neuroplasticity in health and disease

Repetitive, monotonic, and effortful voluntary muscle contractions performed for just a few weeks, i.e., resistance training, can substantially increase maximal voluntary force in the practiced task and can also increase gross motor performance. The increase in motor performance is often accompanied by neuroplastic adaptations in the central nervous system. While historical data assigned functional relevance to such adaptations induced by resistance training, this claim has not yet been systematically and critically examined in the context of motor performance across the lifespan in health and disease. A review of muscle activation, brain and peripheral nerve stimulation, and imaging data revealed that increases in motor performance and neuroplasticity tend to be uncoupled, making a mechanistic link between neuroplasticity and motor performance inconclusive. We recommend new approaches, including causal mediation analytical and hypothesis-driven models to substantiate the functional relevance of resistance training-induced neuroplasticity in the improvements of gross motor function across the lifespan in health and disease.

Relation of chair rising ability to activities of daily living and physical activity in Parkinson's disease

Background

Many persons living with Parkinson’s disease (PD) have difficulty rising from a chair. Impaired ability to perform the chair rise may be associated with low physical activity levels and reduced ability to perform activities of daily living (ADL).

Methods

Cross-sectional analysis was performed in 88 persons with PD to study the association of chair rising ability with ADL and physical activity.

Results

We found that the participants who pushed themselves up from the chair had more severe PD, higher motor impairment and more comorbidity than those who rose from a chair normally. The Unified Parkinson’s Disease Rating Scale ADL (UPDRS-ADL), Schwab and England Activities of Daily Living Scale (SE-ADL) and the Physical Activity Scale for the Elderly (PASE) scores for the participants who pushed themselves up to rise (17.20 ± 7.53; 76.67 ± 13.23; 46.18 ± 52.64, respectively) were significantly poorer than for those who rose normally (10.35 ± 3.79; 87.64 ± 8.30; 112.90 ± 61.40, respectively) (all p < .05). Additionally, PASE scores were significantly poorer for participants who pushed themselves up to rise compared to those who rose slowly (95.21 ± 60.27) (p < .01). Pushing up to rise from a chair was a significant predictor of UPDRS-ADL (β = .357; p < .001; R² = .403), SE-ADL (β = −.266; p = .009; R² = .257) and PASE (β = −.250; p = .016; R² = .162).

Conclusions

Ability to rise from a chair was associated with ADL limitation and physical activity in persons with PD. Poor ability to rise from a chair may prevent persons from living independently and engaging in physical activity.

Defective corticomuscular connectivity during walking in patients with Parkinson's disease

Gait disturbances are common in individuals with Parkinson's disease (PD). Although the basic patterns of walking are thought to be controlled by the brainstem and spinal networks, recent studies have found significant corticomuscular coherence in healthy individuals during walking. However, it still remains unknown how PD affects the cortical control of muscles during walking. As PD typically develops in older adults, it is important to investigate the effects of both aging and PD when examining disorders in patients with PD. Here, we assessed the effects of PD and aging on corticomuscular communication during walking by investigating corticomuscular coherence. We recorded electroencephalographic and electromyographic signals in 10 individuals with PD, 9 healthy older individuals, and 15 healthy young individuals. We assessed the corticomuscular coherence between the motor cortex and two lower leg muscles, tibialis anterior (TA) and medial gastrocnemius, during walking. Older and young groups showed sharp peaks in muscle activation patterns at specific gait phases, whereas the PD group showed prolonged patterns. Smaller corticomuscular coherence was found in the PD group compared with the healthy older group in the α band (8-12 Hz) for both muscles, and in the β band (16-32 Hz) for TA. Older and young groups did not differ in the magnitude of corticomuscular coherence. Our results indicated that PD decreased the corticomuscular coherence during walking, whereas it was not affected by aging. This lower corticomuscular coherence in PD may indicate lower-than-normal corticomuscular communication, although direct or indirect communication is unknown, and may cause impaired muscle control during walking.NEW & NOTEWORTHY Mechanisms behind how Parkinson's disease (PD) affects cortical control of muscles during walking remain unclear. As PD typically develops in the elderly, investigation of aging effects is important to examine deficits regarding PD. Here, we demonstrated that PD causes weak corticomuscular synchronization during walking, but aging does not. This lower-than-normal corticomuscular communication may cause impaired muscle control during walking.

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.

Associations of Motor Symptom Severity and Quality of Life to Motor Task Performance in Upper and Lower Extremities Across Task Complexity in Parkinson's Disease

The authors examined the associations between the performance of upper- and lower-extremity motor tasks across task complexity and motor symptom severity, overall disease severity, and the physical aspects of quality of life in persons with Parkinson's disease. The performance was assessed for three lower-extremity tasks and two upper-extremity tasks of different levels of complexity. The motor symptoms and overall disease severity correlated significantly with all motor tasks with higher correlation coefficients in the complex tasks. Thus, the strength of the association between disease severity or severity of motor symptoms and motor performance is task-specific, with higher values in complex motor tasks than in simpler motor tasks. Mobility-related and activity-of-daily-living-related quality of life correlated with lower-extremity tasks of low and medium complexity and with the complex upper-extremity task, respectively; this suggests that Parkinson's Disease Questionnaire-39 is capable of differentiating between the impact of gross and fine motor function on quality of life.

Similarities and Differences of Gait Patterns in Women and Men With Parkinson Disease With Mild Disability

OBJECTIVE

This study aimed to quantitatively investigate the existence of differences in spatiotemporal and kinematic parameters of gait in men and women with Parkinson disease (PD) using computerized 3-dimensional gait analysis.

DESIGN

Retrospective cohort study.

SETTING

Laboratory of Biomechanics.

PARTICIPANTS

Individuals with PD (N=35; 17 female, 18 male) of mean age 70.7 years characterized by mild disability (Hoehn and Yahr ≤2.5) who were tested in On medication state approximately 60 to 90 minutes after intake of the usual morning Levodopa dose.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Spatiotemporal parameters of gait (speed, stride length, cadence, step width, duration of stance, swing, double support phases) and kinematics of hip, knee, and ankle joints in the sagittal plane.

RESULTS

Men and women exhibit similar spatiotemporal parameters, except for step width (wider in men). In contrast, relevant differences were found in terms of ankle kinematics. In particular, women presented increased ankle dorsiflexion through all the stance phase and mid to late swing phase, and reduced plantarflexion at the stance-swing phase transition.

CONCLUSIONS

Gait patterns of men and women with PD with mild disability are similar in terms of spatiotemporal parameters but characterized by marked differences regarding the ankle kinematics on the sagittal plane. The findings of the present study support the concept that investigations seeking to clarify the complex pathophysiology of PD-related gait disturbances should consider the role played by an individual's sex, thereby achieving more effective designing of physical and rehabilitative treatments.

Considerations and Practical Options for Measuring Muscle Strength: A Narrative Review

Muscle strength impairments are related to mobility limitations and other untoward outcomes. This narrative review, therefore, describes considerations relative to the definition and measurement of muscle strength. Thereafter, practical options for measuring muscle strength are described and their clinimetric properties are delineated. Information provided herein may help students, clinicians, and researchers select the strength tests best suited to their research needs and limitations.

Muscle Fatigue Does Not Change the Effects on Lower Limbs Strength Caused by Aging and Parkinson's Disease

The aim of this study was to determine the impact of aging and Parkinson’s disease (PD) on lower limb muscle strength before and after muscle fatigue. One hundred thirty-five individuals were distributed over seven groups according to their age (20, 30, 40, 50, 60, 70 years old) and disease. Participants performed maximum voluntary isometric contractions (MVIC) in a leg press device followed by the muscle fatigue protocol (repeated sit-to-stand task). Immediately after muscle fatigue (less than 2 min), the MVIC were repeated. The peak force, peak rate of force development (first 50, 100, 200 ms), and root mean square and peak values of the vastus lateralis and vastus medialis muscle activity during MVIC were calculated before and after muscle fatigue. We found more pronounced reductions in lower limb muscle strength parameters (lower limb force, RFD-100 and RFD-200 - p<0.05) in individuals over 50 years of age and with PD. In addition, there was an inverse relation between aging and lower limb muscle strength parameters. The main findings were the lack of changes in peak force, RFDs and muscle activity of the vastus lateralis and vastus medialis after muscle fatigue according to aging and PD, and similar lower limb muscle strength parameters (before and after muscle fatigue) and effect of muscle fatigue in PD compared to the aged groups (60 and 70 years old groups).

Effect of transcranial pulsed electromagnetic fields (T-PEMF) on functional rate of force development and movement speed in persons with Parkinson's disease: A randomized clinical trial

Background

Parkinson’s disease is caused by dopaminergic neurodegeneration resulting in motor impairments as slow movement speed and impaired balance and coordination. Pulsed electromagnetic fields are suggested to have neuroprotective effects, and could alleviate symptoms.

Objective

To study 1) effects of 8-week daily transcranial pulsed electromagnetic field treatment on functional rate of force development and movement speed during two motor tasks with different levels of complexity, 2) if treatment effects depend on motor performance at baseline.

Methods

Ninety-seven persons with Parkinson’s disease were randomized to active transcranial pulsed electromagnetic field (squared bipolar 3 ms pulses, 50 Hz) or placebo treatment with homebased treatment 30 min/day for 8 weeks. Functional rate of force development and completion time of a sit-to-stand and a dynamic postural balance task were assessed pre and post intervention. Participants were sub-grouped in high- and low-performers according to their baseline motor performance level. Repeated measure ANOVAs were used.

Results

Active treatment tended to improve rate of force development during chair rise more than placebo (P = 0.064). High-performers receiving active treatment improved rate of force development during chair rise more than high-performers receiving placebo treatment (P = 0.049, active/placebo: 11.9±1.1 to 12.5±1.9 BW/s ≈ 5% / 12.4±1.3 to 12.2±1.3 BW/s, no change). No other between-treatment-group or between-treatment-subgroup differences were found. Data on rate of force development of the dynamic balance task and completion times of both motor tasks improved but did not allow for between-treatment differentiation.

Conclusion

Treatment with transcranial pulsed electromagnetic fields was superior to placebo regarding functional rate of force development during chair rise among high-performers. Active treatment tended to increase functional rate of force development while placebo did not. Our results suggest that mildly affected persons with Parkinson’s disease have a larger potential for neural rehabilitation than more severely affected persons and indicate that early treatment initiation may be beneficial.

Bilateral deficit in explosive force related to sit-to-stand performance in older postmenopausal women

The purpose of this study was to determine whether the bilateral deficit (BLD) for maximal voluntary force (MVF) and rate of force development (RFD) influences sit-to-stand in older postmenopausal women. Fourteen women performed unilateral and bilateral maximal voluntary contractions during isometric leg-extension. The MVF and RFD over consecutive 50ms periods (0-50, 50-100 and 100-150ms) after force onset and the time to sit-to-stand test were calculated. There was only a BLD for RFD 0-50ms and 50-100ms. The time of sit-to-stand was moderately correlated to BLD for RFD 0-50ms (r=0.505; 95% CI: -0.035 to 0.817; P=0.06), but after controlling for physical activity level the relationship was stronger and statistically significant (r=0.605; 95% CI: 0.109 to 0.859; P=0.029). These results suggest that the BLD for explosive force (0-50ms) might represent a performance-limiting factor for sit-to-stand transfer in postmenopausal women and could be dependent of the physical activity level. Trial registered at Clinical Trials Gov.: NCT02434185.

A Selective Corrective Exercise to Decrease Falling and Improve Functional Balance in Idiopathic Parkinson's Disease

BACKGROUND

Posture instability and unsteady gait disorders in Parkinson's Disease (PD) usually contribute to fall-related fractures. Fall-related trauma in PD is the most common reason for injury. Despite providing modern care for PD patients (PP) in the recent years, anti-PD drugs have no effect on falling. There is an urgent need to administer exercise interventions to reduce falls and related injuries in the rehabilitation program of PP.

OBJECTIVES

To explore the effect of a selective 10-week corrective exercise with an emphasis on gait training activities (GTA) on the number of falls (NOFs), fear of falling, functional balance, timed up and go (TUG) test among PD patients.

PATIENTS AND METHODS

A purposeful sampling was performed on PP who had fallen or were at risk of falling in 2014. The study intervention consisted of a 10-week (3 sessions each week, each lasting 60 min) corrective exercise program. Participants were randomly allocated to control and two exercise groups; the exercise group with balance pad (EGBP) or exercise group with no balance pad (EGNBP). The analysis of variance (ANOVA) and paired t-test were used for comparison between the groups (P ≤ 0.05).

RESULTS

Administrating a selective corrective exercise in exercise group with balance pad (EGBP) showed a significant difference in number of falls (NOF), Fall Efficacy Scale-international (FES-I), Berg balance scale (BBS) (and timed up and go) TUG (P = 0.001); while administrating the same exercise in exercise group with no balance pad (EGNBP) showed no significant difference in NOF (P = 0.225) and a significant difference in FES-I (P = 0.031), BBS (P = 0.047) and TUG (P = 0.012). The control group showed no significant difference in each of the dependent variables.

CONCLUSIONS

Performing a selective corrective exercise on balance pad improves falling and functional balance in idiopathic PD.

Motor intensive anti-gravity training improves performance in dynamic balance related tasks in persons with Parkinson's disease

Recent studies indicate that the effect of training on motor performance in persons with Parkinson's disease (PDP) is dependent on motor intensity. However, training of high motor intensity can be hard to apply in PDP due to e.g. bradykinesia, rigidity, tremor and postural instability. Therefore, the aim was to study the effect of motor intensive training performed in a safe anti-gravity environment using lower-body positive pressure (LBPP) technology on performance during dynamic balance related tasks. Thirteen male PDP went through an 8-week control period followed by 8 weeks of motor intensive antigravity training. Seventeen healthy males constituted a control group (CON). Performance during a five repetition sit-to-stand test (STS; sagittal plane) and a dynamic postural balance test (DPB; transversal plane) was evaluated. Effect measures were completion time, functional rates of force development, directional changes and force variance. STS completion time improved by 24% to the level of CON which was explained by shorter sitting-time and standing-time and larger numeric rate of force change during lowering to the chair, indicating faster vertical directional change and improved relaxation. DPB completion time tended to improve and was accompanied by improvements of functional medial and lateral rates of force development and higher vertical force variance during DPB. Our results suggest that the performance improvements may relate to improved inter-limb coordination. It is concluded that 8 weeks of motor intensive training in a safe LBPP environment improved performance during dynamic balance related tasks in PDP.

Tai Chi Exercise can Improve the Obstacle Negotiating Ability of People with Parkinson's Disease: A Preliminary Study

[Purpose] The purpose of this study was to examine the effects of Tai Chi (TC)-based exercise on dynamic postural control during obstacle negotiation by subjects with mild or moderate Parkinson’s disease (PD). [Subjects] Twelve subjects (mean age, 65.3±6.1 years) diagnosed with idiopathic PD were enrolled for this study. [Methods] All the subjects were tested a week before and 12 weeks after the initiation of the TC exercise. In the test, they were instructed to negotiate an obstacle from the position of quiet stance at a normal speed. They were trained with TC exercise that emphasized multidirectional shift in weight bearing from bilateral to unilateral support, challenging the postural stability, three times per week for 12 weeks. Center of pressure (COP) trajectory variables before and after TC exercise were measured using two force plates. [Results] A comparison of the results between pre- and post-intervention showed a statistically significant improvement in anteroposterior and mediolateral displacement of COP. [Conclusion] Twelve weeks of TC exercise may be an effective and safe form of stand-alone behavioral intervention for improving the dynamic postural stability of patients with PD.

Psychometric properties of 3 functional mobility tests for people with Parkinson disease

BACKGROUND

Standardized outcome measures with high clinical utility are of paramount importance for clinical practice.

OBJECTIVE

The purpose of this study was to examine interrater and intrarater reliability, construct validity, discriminant ability, and smallest detectable differences of the sit-to-stand test (STS), Timed "Up & Go" Test (TUG), and bed mobility test for people with Parkinson disease (PD).

DESIGN

A cross-sectional, psychometric evaluation study was conducted.

METHODS

A group of individuals with PD (PD group) and a group of individuals who were healthy (control group) were recruited through local PD groups and assessed in a movement laboratory in their "on" phase. Measurements of time to perform one STS, TUG, and bed mobility test were collected based on video recordings of that single performance.

RESULTS

Thirty-eight individuals with PD (Hoehn and Yahr stages I-IV) and 19 age-matched control participants were recruited. Intraclass correlation coefficients for interrater and intrarater reliability for the PD group ranged from .95 to .99. Bland-Altman plots showed mean differences close to zero and narrow confidence intervals. Construct validity was established by means of moderate to good Spearman rho correlation coefficients with part III of the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr stage (range=.51-.63). Timings of all tests discriminated participants in the PD group from those in the control group and participants in the PD group in Hoehn and Yahr stages I and II from those in Hoehn and Yahr stages III and IV but did not discriminate "nonfallers" or those with single falls from repeat "fallers" or "nonfreezers" from "freezers." Applicable smallest detectable differences were established.

LIMITATIONS

The results are not generalizable to people in the late stage of PD (Hoehn and Yahr stage IV: n=3).

CONCLUSIONS

Timings of video recordings of 3 functional mobility tests with high clinical utility showed good psychometric properties for community-dwelling, ambulatory people with PD.

Parkinson disease and exercise

Parkinson disease (PD) is a progressive, neurodegenerative movement disorder. PD was originally attributed to neuronal loss within the substantia nigra pars compacta, and a concomitant loss of dopamine. PD is now thought to be a multisystem disorder that involves not only the dopaminergic system, but other neurotransmitter systems whose role may become more prominent as the disease progresses (189). PD is characterized by four cardinal symptoms, resting tremor, rigidity, bradykinesia, and postural instability, all of which are motor. However, PD also may include any combination of a myriad of nonmotor symptoms (195). Both motor and nonmotor symptoms may impact the ability of those with PD to participate in exercise and/or impact the effects of that exercise on those with PD. This article provides a comprehensive overview of PD, its symptoms and progression, and current treatments for PD. Among these treatments, exercise is currently at the forefront. People with PD retain the ability to participate in many forms of exercise and generally respond to exercise interventions similarly to age-matched subjects without PD. As such, exercise is currently an area receiving substantial research attention as investigators seek interventions that may modify the progression of the disease, perhaps through neuroprotective mechanisms.

Central Factors Explain Muscle Weakness in Young Fallers With Parkinson’s Disease

Background. Muscle weakness in old Parkinson’s disease (PD) patients has been shown to impair their mobility, although the specific origin of this weakness and its relation to falls has not been well examined in young patients. Objective. This study aimed to analyze the possible contribution of central factors to muscle weakness of the triceps surae and quadriceps femoris muscles in young faller and nonfaller PD patients. Methods. Twenty-six young PD patients (fallers, n = 13 and nonfallers, n = 13) and 15 matched healthy controls performed several isometric maximal voluntary knee extension and plantar flexion contractions (MVC) of the most affected leg on a dynamometer. We estimated the maximal resultant agonist moments, the antagonistic moment of hamstrings and tibialis anterior during MVCs and the activation deficit of the quadriceps femoris and triceps surae muscles. Results. Only the Parkinson fallers showed significantly lower muscle strength, higher antagonistic moments and higher activation deficit compared with controls. Multiple regression analysis showed that the antagonistic moments and the activation deficit explained about 39% and 27%, of the variance in the maximal resultant moments of the knee extensors and the plantar flexors, respectively. Conclusions. Our findings suggest that Parkinson fallers are affected by strength impairments arising from the central nervous system and not from the peripheral muscle contractile capacity, even at early stages of the disease and young age. High-intensity resistance training may help enhance neural drive and decrease unwanted antagonistic moments and reduce the risk of falls.

Progressive resistance exercise improves strength and physical performance in people with mild to moderate Parkinson's disease: a systematic review

QUESTION

Does progressive resistance exercise improve strength and measures of physical performance in people with Parkinson's disease?

DESIGN

Systematic review with meta-analysis of randomised and quasi-randomised controlled trials.

PARTICIPANTS

People with Parkinson's disease, regardless of gender or level of disability.

INTERVENTION

Progressive resistance exercise, defined as involving repetitive, strong, or effortful muscle contractions and progression of load as the participant's abilities changed.

OUTCOME MEASURES

Measures of muscle strength (maximum voluntary force production) - either continuous (force, torque, work, EMG) or ordinal (manual muscle test) - and physical performance measures: sit-to-stand time, fast and comfortable walking speeds, 6-min walk test, stair descent and ascent, the Activities-specific Balance Confidence scale, Timed Up and Go test, and the Short Physical Performance Battery.

RESULTS

Four (quasi-) randomised trials were included, three of which reported data that could be pooled in a meta-analysis. Progressive resistance exercise increased strength, with a standardised mean difference 0.50 (95% CI 0.05 to 0.95), and had a clinically worthwhile effect on walking capacity, with a mean difference of 96 metres (95% CI 40 to 152) among people with mild to moderate Parkinson's disease. However, most physical performance outcomes did not show clinically worthwhile improvement after progressive resistance exercise.

CONCLUSION

This review suggests that progressive resistance exercise can be effective and worthwhile in people with mild to moderate Parkinson's disease, but carryover of benefit does not occur for all measures of physical performance. The current evidence suggests that progressive resistance training should be implemented in Parkinson's disease rehabilitation, particularly when the aim is to improve walking capacity.

Effects of Treadmill Exercise on the Recovery of Dopaminergic Neuron Loss and Muscle Atrophy in the 6-OHDA Lesioned Parkinson's Disease Rat Model

This study was to determine the effect of exercise on the recovery of dopaminergic neuron loss and muscle atrophy in 6-OHDA-induced hemi Parkinson's disease model. Exercise was loaded twice per day for 30 minutes each time, at 5 days after 6-OHDA lesioning and continued for 16 days using a treadmill. Exercise significantly increased the number of tyrosine hydroxylase positive neuron in the lesioned substantia nigra and the expression level of tyrosine hydroxylase in the striatum compared with the control group. To examine which signaling pathways may be involved in the exercise, the phosphorylation of GSK3β and ERK were observed in the striatum. In the control group, basal level of GSK3β phosphorylation was less than in both striatum, but exercise increased it. ERK phosphorylation decreased in the lesioned striatum, but exercise recovered it. These findings suggest that exercise inactivates GSK3β by phosphorylation which may be involved in the neuroprotective effect of exercise on the 6-OHDA-induced cell death. In the exercise group, weight, and Type I and II fiber cross-sectional area of the contralateral soleus significantly recovered and expression of myosin heavy chain and Akt and ERK phosphorylation significantly increased by exercise. These results suggest that exercise recovers Parkinson's disease induced dopaminergic neuron loss and contralateral soleus muscle atrophy.

Motor and cognitive impairments in Parkinson disease: relationships with specific balance and mobility tasks

BACKGROUND

Balance and mobility problems are common for people with Parkinson disease (PD).

OBJECTIVE

To determine the relationships of motor and cognitive impairments with specific balance and mobility task performance.

METHODS

A total of 82 community-dwelling people with idiopathic PD were tested "on" medication. Impairments measured included leg extensor and hip abductor muscle power, freezing of gait, dyskinesia, and executive function. Balance and mobility were classified into tasks requiring anticipatory control with a change in base of support, anticipatory control without a change in support, and reactive adjustments in response to external perturbations. Associations between impairments and tasks were examined using univariable and multivariable linear regression models.

RESULTS

Univariable models revealed that muscle power was significantly related to balance and mobility, explaining 7% to 33% of the variability in task performance. Freezing of gait, dyskinesia, and executive function were not consistently related to task performance. Multivariable models that included all impairments plus disease severity, age, gender, and height explained 5% to 43% of the variability in balance and mobility tasks. Leg muscle power was the only impairment with a consistent association with performance of tasks involving anticipatory control with a change in base of support (β = 0.2 to 0.5), but the association of each muscle group was specific to individual tasks.

CONCLUSION

Information gained from this study about the relationships between impairments and specific balance and mobility tasks may be able to guide the development of interventional strategies for people with PD.

Validity and variability of the 5-repetition sit-to-stand test in patients with multiple sclerosis

PURPOSE

To investigate; (i) the relationship between the 5STS-test and lower extremity muscle strength and balance, and (ii) the variability of the 5STS-test in multiple sclerosis (MS) patients.

METHOD

22 MS patients were divided into two groups (Group A and Group B) who completed one 5STS familiarization test session and two testing sessions. In Group A, session 1 also included assessment of lower extremity muscle strength. Session 2 and 3 involved completion of two 5STS-tests and assessment of balance. In Group B, session 2 and 3 involved completion of two rounds of two 5STS-tests separated by a 30 min break.

RESULTS

Significant correlations were found between the 5STS-test and isometric and isokinetic knee flexor and extensor muscle strength of the most affected leg (R = -0.60 to -0.77), and between the 5STS-test and balance performance (R = 0.69). Intra-assessor day-to-day variability, intra-assessor test-retest variability and intra-assessor variability within test were 25.5, 22.3, and 23.1%, respectively. Inter-assessor variability within test and inter-assessor variability were 23.4 and 5.9%, respectively.

CONCLUSIONS

The 5STS-test is related to lower extremity muscle strength and to balance performance in MS patients. For interventional purposes, a change of >25% can be regarded as a real change.

Quadriceps muscle weakness, activation deficits, and fatigue with Parkinson disease

BACKGROUND

People with Parkinson disease (PD) typically have complaints of weakness. The mechanisms underlying this deficit have not been well established, although many factors may contribute.

OBJECTIVE

This investigation aimed to characterize quadriceps muscle weakness and activation failure in people with PD and explore whether these deficits were related to disease severity. The authors further sought to examine quadriceps muscle fatigability.

METHODS

This was a cross-sectional comparison of 17 people with mild-severe PD and 17 healthy adults matched by age, sex, and body mass index (BMI). The Unified Parkinson's Disease Rating Scale motor score (UPDRS motor) ranged from 9.5 to 61.0. Participants were divided into those with low-PD motor signs (UPDRS motor < 31.7) and high-PD motor signs (UPDRS motor ≥ 31.7). Measures of quadriceps performance included isometric torque, central activation using doublet interpolation, and an isokinetic fatigue test.

RESULTS

Participants with high-PD motor signs had significantly more quadriceps weakness and central activation deficits than those with low-PD motor signs or healthy controls. Strength and activation deficits correlated strongly with UPDRS motor score. Quadriceps muscle fatigue was present in healthy controls and in those with low-PD motor signs but not in those with high-PD motor signs.

CONCLUSIONS

These findings provide additional evidence for lower-extremity strength loss with PD; central activation deficits may account for some of the strength deficits, especially with increased PD motor signs. Also, muscle fatigue did not occur in individuals with a greater degree of PD motor signs, most likely because of insufficient central activation to allow for muscle overload to induce metabolic fatigue.

Gait difficulty, postural instability, and muscle weakness are associated with fear of falling in people with Parkinson's disease

The present study aimed to examine the contribution of gait impairment, postural stability and muscle weakness to the level of fear of falling in people with Parkinson's disease (PD). Fifty-seven community-dwelling individuals with PD completed the study. Fear of falling was assessed by the Activities-specific Balance Confidence (ABC) scale. Postural stability and gait difficulty were determined by the posture and gait subscores of the Unified Parkinson's Disease Rating Scale (UPDRS-PG). A Cybex dynamometer was used to measure isokinetic knee muscle strength. Individuals with PD achieved a mean ABC score of 73.6 ± 19.3. In the multiple regression analysis, after accounting for basic demographics, fall history and disease severity, the UPDRS-PG score remained independently associated with the ABC score, accounting for 13.4% of the variance (P < 0.001). The addition of knee muscle strength significantly improved the prediction model and accounted for an additional 7.3% of the variance in the ABC score (P < 0.05). This is the first study to demonstrate that the UPDRS-PG score and knee muscle strength are important and independent determinants of the level of fear of falling in individuals with PD. Improving balance, gait stability and knee muscle strength could be crucial in promoting balance confidence in the appropriately targeted PD population.

Exercício aeróbio e fortalecimento muscular melhoram o desempenho funcional na doença de Parkinson

INTRODUÇÃO: Indivíduos com doença de Parkinson (DP) apresentam déficits motores na marcha, postura e equilíbrio e tendem a apresentar redução mais acentuada do nível de atividade física do que indivíduos assintomáticos da mesma idade. O declínio físico pode estar associado à perda de força muscular, da capacidade física e piora do desempenho funcional na DP. OBJETIVO: Avaliar os efeitos de um programa de fortalecimento e condicionamento aeróbio no desempenho funcional e na capacidade física de indivíduos com DP. MATERIAIS E MÉTODOS: Dezessete indivíduos, com média de idade de 60,35 ± 9,94 anos e estágios I a III da Hoehn e Yahr, participaram de um programa de exercícios três vezes por semana durante 12 semanas. Avaliou-se a força muscular por meio do dinamômetro manual, o desempenho funcional por meio da Unified Parkinson Disease Rating Scale (UPDRS), avaliou-se também a velocidade da marcha e habilidade em usar escadas e a capacidade física por meio do perfil de atividade humana (PAH). Utilizou-se a estatística descritiva, testes t e ANOVA para medidas repetidas para a análise. RESULTADOS E DISCUSSÃO: Os dorsoflexores bilaterais foram o único grupo muscular a apresentar maior torque após a intervenção (F = 7,93; p = 0,008). Houve ganho nas medidas de desempenho funcional: velocidade da marcha (p = 0,028), velocidade para subir (p = 0,001) e descer (p = 0,002) escadas, no escore total da UPDRS (p = 0,007) e do PAH (p < 0,0001). CONSIDERAÇÕES FINAIS: O uso combinado de condicionamento aeróbio e fortalecimento muscular resultou em melhoras no desempenho funcional e na capacidade física de indivíduos com DP leve a moderada.

Lower extremity isokinetic muscle strength in patients with Parkinson's disease

We evaluated lower extremity isokinetic muscle strength to determine affected muscle groups and their dependence on movement velocity, and to establish the relationship between muscle strength and clinical severity, as well as muscle strength and falls, in Parkinson's disease (PD). Twenty-five patients diagnosed with PD and 24 healthy volunteers were enrolled in this study. Lower extremity muscle strength was measured using an isokinetic dynamometer. Each participant's clinical status was examined in accordance with the Unified Parkinson's Disease Rating Scale; fall history was also recorded. We observed a significant decrease in isokinetic muscle strength in the patient group, especially in both hip and knee flexors and extensors. Decreased muscle strength was independent of velocity, and correlated with clinical severity and falls. Movement velocity-independent lower extremity isokinetic muscle weakness has been observed in patients with PD, especially in the knee and hip joints. The evaluation of isokinetic muscle strength may be a useful tool for the assessment of clinical severity and falls in PD.

Effects of moderate-volume, high-load lower-body resistance training on strength and function in persons with Parkinson's disease: a pilot study

Background. Resistance training research has demonstrated positive effects for persons with Parkinson's disease (PD), but the number of acute training variables that can be manipulated makes it difficult to determine the optimal resistance training program. Objective. The purpose of this investigation was to examine the effects of an 8-week resistance training intervention on strength and function in persons with PD. Methods. Eighteen men and women were randomized to training or standard care for the 8-week intervention. The training group performed 3 sets of 5–8 repetitions of the leg press, leg curl, and calf press twice weekly. Tests included leg press strength relative to body mass, timed up-and-go, six-minute walk, and Activities-specific Balance Confidence questionnaire. Results. There was a significant group-by-time effect for maximum leg press strength relative to body mass, with the training group significantly increasing their maximum relative strength (P < .05). No other significant interactions were noted (P > .05). Conclusions. Moderate volume, high-load weight training is effective for increasing lower-body strength in persons with PD.

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

PURPOSE

Muscle strength (force) and power (force x velocity) are reduced in Parkinson's disease (PD). Reduced muscle power is associated with slower walking velocity and falls in the older population, but these associations in people with PD have not previously been investigated. This study investigated the relationships between leg extensor muscle power and strength with walking speed and past falls in people with PD.

PARTICIPANTS AND METHODS

Forty people with mild to moderate PD were assessed. Walking velocity was measured over 10 m and the number of falls the participant reported having in the past 12 months was recorded. Leg extensor muscle power and strength were measured using a Keiser leg press machine.

RESULTS

Muscle power explained more than half of the variance (R(2) = 0.54) in walking velocity and remained significantly (p < 0.05) associated with walking velocity in models which included Unified Parkinson's Disease Rating Scale (UPDRS) motor scores. Participants with low muscle power were 6 times more likely to report multiple falls in the past year than those with high muscle power (OR = 6.0, 95% CI 1.1 to 33.3), though this association between falls and power was no longer significant in models which included UPDRS motor scores (p = 0.09).

CONCLUSION

Muscle power is a significant determinant of walking velocity in PD even after adjusting for UPDRS motor score. Muscle power training warrants investigation in people with PD.

Bradykinesia, muscle weakness and reduced muscle power in Parkinson's disease

Muscle power (force x velocity) could clarify the relationship between weakness and bradykinesia in Parkinson's disease (PD). The aims of this study were to determine if patients with PD were weaker and/or less powerful in their leg extensor muscles than a neurologically normal control group and to determine the relative contributions of force and movement velocity/bradykinesia to muscle power in PD. Forty patients with PD and 40 controls were assessed. Strength in Newtons (N) was measured as the heaviest load the participant could lift. Power in Watts (W) was measured by having the participant perform lifts as fast as possible. The PD group were 172 N weaker (95% CI 28-315) and 124 W less powerful at peak power (95% CI 32-216) than controls. However, velocity at maximal power was only reduced compared with controls when lifting light to medium loads. When lifting heavy loads bradykinesia was no longer apparent in the PD group. These results suggest that reduced muscle power in PD at lighter loads arises from weakness and bradykinesia combined, but at heavier loads arises only from weakness. The absence of bradykinesia in the PD group when lifting heavy loads warrants further investigation.

Impaired leg extensor strength in individuals with Parkinson disease and relatedness to functional mobility

Previous investigations have demonstrated leg strength deficits in persons with Parkinson's disease (PD) as compared to neurologically-normal adults. However, the exact mode of contraction by which strength is assessed may determine how closely such deficits are related to functional performance. The purpose of this study was to better understand the relationship of strength and functional mobility in persons with PD (n = 17, mean H&Y stage = 2.0) via comparison to a group of similar age healthy controls (n = 10) using a multi-joint isometric test of strength and various measures of functional mobility. Tests included isometric leg press maximum force relative to body mass, the Activities-specific Balance Confidence scale (ABC), postural sway under various unilateral stance and visual conditions, and the timed up and go (TUG). Relative force (p = 0.044) and ABC questionnaire mean scores (p < 0.001), showed controls performing better than PD subjects. The control group performed better than the PD group for length of path of the center of pressure except in the eyes closed positions (p < 0.05 for all). TUG time (p = 0.052) was not significantly different between the PD group and healthy controls. Leg press maximum force relative to body mass was however significantly correlated with TUG time (r = -0.68, p = 0.003) in persons with PD. There were no gender differences for any variables. These results suggest that some balance and functional mobility task performances are more worse for persons with mild-to-moderate PD than for neurologically-normal age-matched controls, which may be influenced by lessened lower extremity multi-joint strength. Strength training of the lower extremity utilizing such multi-joint actions may be beneficial for this population.

Exercise therapy for prevention of falls in people with Parkinson's disease: a protocol for a randomised controlled trial and economic evaluation

BACKGROUND

People with Parkinson's disease are twice as likely to be recurrent fallers compared to other older people. As these falls have devastating consequences, there is an urgent need to identify and test innovative interventions with the potential to reduce falls in people with Parkinson's disease. The main objective of this randomised controlled trial is to determine whether fall rates can be reduced in people with Parkinson's disease using exercise targeting three potentially remediable risk factors for falls (reduced balance, reduced leg muscle strength and freezing of gait). In addition we will establish the cost effectiveness of the exercise program from the health provider's perspective.

METHODS/DESIGN

230 community-dwelling participants with idiopathic Parkinson's disease will be recruited. Eligible participants will also have a history of falls or be identified as being at risk of falls on assessment. Participants will be randomly allocated to a usual-care control group or an intervention group which will undertake weight-bearing balance and strengthening exercises and use cueing strategies to address freezing of gait. The intervention group will choose between the home-based or support group-based mode of the program. Participants in both groups will receive standardized falls prevention advice. The primary outcome measure will be fall rates. Participants will record falls and medical interventions in a diary for the duration of the 6-month intervention period. Secondary measures include the Parkinson's Disease Falls Risk Score, maximal leg muscle strength, standing balance, the Short Physical Performance Battery, freezing of gait, health and well being, habitual physical activity and positive and negative affect schedule.

DISCUSSION

No adequately powered studies have investigated exercise interventions aimed at reducing falls in people with Parkinson's disease. This trial will determine the effectiveness of the exercise intervention in reducing falls and its cost effectiveness. This pragmatic program, if found to be effective, has the potential to be implemented within existing community services.

TRIAL REGISTRATION

The protocol for this study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12608000303347).

Parkinson's disease and resistive exercise: rationale, review, and recommendations

Individuals with Parkinson's disease (PD) are not only burdened with disease-specific symptoms (i.e., bradykinesia, rigidity, and tremor), but are also confronted with age-associated progressive loss of physical function, perhaps to a greater extent than neurologically normal adults. Suggestions for the inclusion of resistive exercise into treatment to attenuate these symptoms were made over 10 years ago, yet very few well controlled investigations are available. The objective of this review is to establish a clear rationale for the efficacy of resistance training in individuals with PD. Specifically, we highlight musculoskeletal weakness and its relationship to function as well as potential training-induced adaptive alterations in the neuromuscular system. We also review the few resistance training interventions currently available, but limit this review to those investigations that provide a quantitative exercise prescription. Finally, we recommend future lines of inquiry warranting further attention and call to question the rationale behind current exercise prescriptions. The absence of reports contraindicating resistive exercise, the potential for positive adaptation, and the noted benefits of resistance training in other populations may provide support for its inclusion into a treatment approach to PD.

Resistance training with creatine monohydrate improves upper-body strength in patients with Parkinson disease: a randomized trial

BACKGROUND

Persons with Parkinson disease (PD) exhibit decreased muscular fitness including decreased muscle mass, muscle strength, bioenergetic capabilities and increased fatigability.

OBJECTIVE

This purpose of this investigation was to evaluate the therapeutic effects of resistance training with and without creatine supplementation in patients with mild to moderate PD.

METHODS

Twenty patients with idiopathic PD were randomized to receive creatine monohydrate supplementation plus resistance training (CRE) or placebo (lactose monohydrate) plus resistance training (PLA), using a double-blind procedure. Creatine and placebo supplementation consisted of 20 g/d for the first 5 days and 5 g/d thereafter. Both groups participated in progressive resistance training (24 sessions, 2 times per week, 1 set of 8-12 repetitions, 9 exercises). Participants performed 1-repetition maximum (1-RM) for chest press, leg extension, and biceps curl. Muscular endurance was evaluated for chest press and leg extension as the number of repetitions to failure using 60% of baseline 1-RM. Functional performance was evaluated as the time to perform 3 consecutive chair rises.

RESULTS

Statistical analyses (ANOVA) revealed significant Group x Time interactions for chest press strength and biceps curl strength, and post hoc testing revealed that the improvement was significantly greater for CRE. Chair rise performance significantly improved only for CRE (12%, P=.03). Both PLA and CRE significantly improved 1-RM for leg extension (PLA: 16%; CRE: 18%). Muscular endurance improved significantly for both groups.

CONCLUSIONS

These findings demonstrate that creatine supplementation can enhance the benefits of resistance training in patients with PD.