Michael J. Falvo

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

Individuals with Parkinsons 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.

Relationship of jumping and agility performance in female volleyball athletes.

Court sports often require more frequent changes of direction (COD) than field sports. Most court sports require 180= turns over a small distance, so COD in such sports might be best evaluated with an agility test involving short sprints and sharp turns. The purposes of this study were to (a) quantify vertical and horizontal force during a COD task, (b) identify possible predictors of court-sport–specific agility performance, and (c) examine performance difference between National Collegiate Athletic Association Division I, II, and III athletes. Twenty-nine collegiate female volleyball players completed a novel agility test, countermovement (CM) and drop jump tests, and an isometric leg extensor test. The number of athletes by division was as follows: I (n = 9), II (n = 11), and III (n = 9). The agility test consisted of 4 5-meter sprints with 3 180= turns, including 1 on a multiaxial force platform so that the kinetic properties of the COD could be identified. One-way analysis of variance revealed that Division I athletes had significantly greater countermovement jump heights than Division III, and the effect size comparisons (Cohens d) showed large-magnitude differences between Division I and both Divisions II and III for jump height. No other differences in performance variables were noted between divisions, although effect sizes reached moderate values for some comparisons. Regression analysis revealed that CM displacement was a significant predictor of agility performance, explaining approximately 34% of the variance. Vertical force was found to account for much of the total force exerted during the contact phase of the COD task, suggesting that performance in the vertical domain may limit the COD task used herein. This study indicates that individuals with greater CM performance also have quicker agility times and suggests that training predominantly in the vertical domain may also yield improvements in certain types of agility performance. This may hold true even if such agility performance requires a horizontal component.

Six-Minute Walk Distance in Persons With Parkinson Disease: A Hierarchical Regression Model

OBJECTIVES To determine the six-minute walk distance (6MWD) in subjects with Parkinson disease (PD) and to determine the impairments that contribute to walking capacity. DESIGN Descriptive cross-sectional study of subjects with PD. SETTING University laboratory. PARTICIPANTS Subjects with PD (N=75; 65.0+/-9.5y) of mild to moderate severity, as defined by an average Hoehn and Yahr (HY) rating of 2.0+/-0.4 and Unified Parkinson Disease Rating Scale (UPDRS) motor score of 27+/-8.9, were tested on medication. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Subjects were administered the motor subsection of the UPDRS and completed the following tests: Berg Balance Scale (BBS), Timed Up & Go (TUG), and six-minute walk test. In addition, they also provided self-reports of freezing of gait and number of falls in the past 6 months. RESULTS The average 6MWD was 391.6+/-99.9 m. All of the aforementioned tests, with the exception of fall number (P=.07), correlated significantly with 6MWD (r range, -.64 to .55). By using a hierarchical regression model, we entered age, HY, and UPDRS motor score into the first block (ie, set of independent variables) to represent parkinsonian characteristics, which explained a significant amount of variability in 6MWD (R2=.196, P<.001). The second block entered (eg, functional measures scores, self-reports) explained a significant amount of additional variability (R2 change=.355, P<.001). The TUG, BBS, and number of falls contributed independently in the presence of all independent variables. CONCLUSIONS The 6MWD in subjects with PD is explained in part by disease-specific characteristics and perhaps to a greater extent by impaired balance and predisposition to falling. Training targeted at improving balance and reducing falling risk factors may increase 6MWD (ie, walking capacity) in subjects with PD.

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

Previous investigations have demonstrated leg strength deficits in persons with Parkinsons 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.

Prior exercise and antioxidant supplementation: effect on oxidative stress and muscle injury

BackgroundBoth acute bouts of prior exercise (preconditioning) and antioxidant nutrients have been used in an attempt to attenuate muscle injury or oxidative stress in response to resistance exercise. However, most studies have focused on untrained participants rather than on athletes. The purpose of this work was to determine the independent and combined effects of antioxidant supplementation (vitamin C + mixed tocopherols/tocotrienols) and prior eccentric exercise in attenuating markers of skeletal muscle injury and oxidative stress in resistance trained men.MethodsThirty-six men were randomly assigned to: no prior exercise + placebo; no prior exercise + antioxidant; prior exercise + placebo; prior exercise + antioxidant. Markers of muscle/cell injury (muscle performance, muscle soreness, C-reactive protein, and creatine kinase activity), as well as oxidative stress (blood protein carbonyls and peroxides), were measured before and through 48 hours of exercise recovery.ResultsNo group by time interactions were noted for any variable (P > 0.05). Time main effects were noted for creatine kinase activity, muscle soreness, maximal isometric force and peak velocity (P < 0.0001). Protein carbonyls and peroxides were relatively unaffected by exercise.ConclusionThere appears to be no independent or combined effect of a prior bout of eccentric exercise or antioxidant supplementation as used here on markers of muscle injury in resistance trained men. Moreover, eccentric exercise as used in the present study results in minimal blood oxidative stress in resistance trained men. Hence, antioxidant supplementation for the purpose of minimizing blood oxidative stress in relation to eccentric exercise appears unnecessary in this population.

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 Parkinsons 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.

Review of Exercise-Induced Muscle Injury: Relevance for Athletic Populations

Exercise-induced skeletal muscle injury is well understood as the product of unfamiliar or strenuous physical activity. Eccentric or lengthening actions are primarily responsible for inducing injury, which subsequently leads to a variety of signs and symptoms. Although significant research supports this finding, most observations are specific to untrained individuals. In addition, many protocols designed both to induce muscle injury and assess performance following the injury are dissimilar from those utilized by physically trained individuals or are impractical in relation to athletic performance or both. Therefore, difficulty may arise when extrapolating information, from the available literature and applying the findings to athletic populations. This review addresses the efficacy of applying our current understanding of exercise-induced skeletal muscle injury to a physically trained population as well as highlights concerns that require future investigation.

Effect of low-dose, short-duration creatine supplementation on anaerobic exercise performance.

To examine the efficacy of a low-dose, short-duration creatine monohydrate supplement, 40 physically active men were randomly assigned to either a placebo or creatine supplementation group (6 g of creatine monohydrate per day). Testing occurred before and at the end of 6 days of supplementation. During each testing session, subjects performed three 15-second Wingate anaerobic power tests. No significant (p > 0.05) group or time differences were observed in body mass, peak power, mean power, or total work. In addition, no significant (p > 0.05) differences were observed in peak power, mean power, or total work. However, the change in the rate of fatigue of total work was significantly (p < 0.05) lower in the creatine supplementation group than in the placebo group, indicating a reduced fatigue rate in subjects supplementing with creatine compared with the placebo. Although the results of this study demonstrated reduced fatigue rates in patients during high-intensity sprint intervals, further research is necessary in examining the efficacy of low-dose, short-term creatine supplementation.

Repeated bout effect is absent in resistance trained men: An electromyographic analysis

A prior bout of exercise is well known to confer protection from subsequent eccentric bouts (i.e. repeated bout effect; RBE), which may be fostered through neural adaptations, specifically a shift in the frequency content of the surface electromyogram (EMG). It is currently not clear whether chronically resistance trained men are capable of a RBE driven by neural adaptations. Eleven resistance trained men (23.5+/-3.4 yrs) performed 100 eccentric actions of the barbell bench press exercise, followed by an equivalent bout 14 days later. Indirect markers of muscle damage (i.e. force production, soreness) along with surface EMG were measured before and through 48 h of recovery. Median frequency and maximal isometric force demonstrated time main effects (p>0.05), but no RBE. A prior bout of eccentric exercise does not confer a RBE for indirect markers of muscle injury or elicit changes in the frequency content of the EMG signal in resistance trained men.

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.