This study provides evidence of a specific therapeutic effect of treadmill training on Parkinsonian gait and balance. Walking on a treadmill may be used as an easy, effective and accessible way to improve the stride length and balance in PD patients.

No abstract

Central and peripheral fatigue have been explored during and after running or cycling exercises. However, the fatigue mechanisms associated with a short maximal cycling exercise (30 s Wingate test) have not been investigated. In this study, 10 volunteer subjects performed several isometric voluntary contractions using the leg muscle extensors before and after two bouts of cycling at 25% of maximal power output and two bouts of Wingate tests. Transcranial magnetic stimulation (TMS) and electrical motor nerve stimulation (NM) were applied at rest and during the voluntary contractions. Maximal voluntary contraction (MVC), voluntary activation (VA), twitch amplitude evoked by electrical nerve stimulation, M wave and motor potential evoked by TMS (MEP) were recorded. MVC, VA and twitch amplitude evoked at rest by NM decreased significantly after the first and second Wingate tests, indicating central and peripheral fatigue. MVC and VA, but not the twitch amplitude evoked by NM, recovered before the second Wingate test. These results suggest that the Wingate test results in a decrease in MVC associated with peripheral and central fatigue. While the peripheral fatigue is associated with an intramuscular impairment, the central fatigue seems to be the main reason for the Wingate test-induced impairment of MVC.

Patients with Parkinson's disease (PD) improve gait after treadmill training and while they are walking over the treadmill. However, the mechanisms of these improvements have not been addressed. We designed a treadmill simulator without a belt that could move on a walkway in a constant speed, in order to explore the mechanism underlying treadmill walking improvements in PD. All subjects were tested in three different sessions (treadmill, simulator(assisted) and simulator(not assisted)). In each session, subjects first walked overground and then walked using the treadmill or simulator with the hands over the handrails (simulator(assisted)) or with the hands free (simulator(not assisted)). Step length, cadence, double support time, swing time, support time and the coefficient of variation (CV) of step time and double support time were recorded. Over the treadmill PD patients increased their step length and reduced significantly their cadence and CV of double support time in comparison with overground walking. In the simulator(assisted) condition PD patients reduced significantly the CV of double support time in comparison with overground walking. With the simulator(not assisted) both groups decreased their step length and increased their cadence and CV of double support time, compared with walking overground. These findings suggest that the step length improvement observed in PD patients, walking over a treadmill, is due to the proprioceptive information generated by the belt movement, since no improvement was reported when patients using a treadmill simulator.

The purpose of the present systematic review and meta-analysis was to explore the effects of transcranial direct current stimulation (tDCS) on endurance (i.e., time to task failure (TTF)) and maximal voluntary contraction (MVC). Furthermore, we aimed to analyze whether the duration of stimulation, the brain region targeted for stimulation, and the task performed could also influence motor performance. We performed a systematic literature review in the databases MEDLINE and Web of Science. The short-term effects of anodal tDCS and sham stimulation (placebo) were considered as experimental and control conditions, respectively. A total of 31 interventions were included (MVC = 13; TTF = 18). Analysis of the strength-related tDCS studies showed small improvements in the MVC (SMD = 0.19; 95% CI = −0.02, 0.41; p = 0.08). However, the results of the endurance-related interventions indicated a moderate effect on TTF performance (SMD = 0.26; 95% CI = 0.07, 0.45; p = 0.008). Furthermore, the sub-analysis showed that anodal tDCS over M1 and stimulation durations longer than 10 min produced the best results in terms of TTF performance enhancement. Additionally, the effects of anodal tDCS were larger during full body exercises (i.e., cycling) when compared to uniarticular tasks. In conclusion, the current meta-analysis indicated that anodal tDCS leads to small and moderate effects on MVC and TTF, respectively.

Collectively, the present data suggest that in spite of the changes occurring in soleus strength and thickness, 4 weeks of low-load resistance training, with or without BFR, does not cause any change in neural drive or motoneuronal excitability.

This study aimed to compare mechanical, metabolic, and perceptual responses between two traditional (TR) and four cluster (CL) set configurations. In a counterbalanced randomized order, 11 men were tested with the following protocols in separate sessions (sets × repetitions [inter-repetition rest]): TR1: 3×10 [0-s]; TR2: 6×5 [0-s]; CL1: 3×10 [10-s]; CL2: 3×10 [15-s]; CL3: 3×10 [30-s]); CL4: 1×30 [15-s]). The exercise (full-squat), number of repetitions (30), inter-set rest (5 min), and resistance applied (10RM) was the same for all set configurations. Mechanical fatigue was quantified by measuring the mean propulsive velocity during each repetition, and the change in countermovement jump height observed after each set and after the whole training session. Metabolic and perceptual fatigue were assessed via the blood lactate concentration and the OMNI perceived exertion scale measured after each training set, respectively. The mechanical, metabolic, and perceptual measures of fatigue were always significantly higher for the TR1 set configuration. The two set configurations that most minimized the mechanical measures of fatigue were CL2 and CL3. Perceived fatigue did not differ between the TR2, CL1, CL2 and CL3 set configurations. The lowest lactate concentration was observed in the CL3 set configuration. Therefore, both the CL2 and CL3 set configurations can be recommended because they maximize mechanical performance. However, the CL2 set configuration presents two main advantages with respect to CL3: (1) it reduces training session duration, and (2) it promotes higher metabolic stress, which to some extent may be beneficial for inducing muscle strength and hypertrophy gains.

Romero-Arenas, S, Calderón-Nadal, G, Alix-Fages, C, Jerez-Martínez, A, Colomer-Poveda, D, and Márquez, G. Transcranial direct current stimulation does not improve countermovement jump performance in young healthy men. J Strength Cond Res 35(10): 2918–2921, 2021—The main purpose of this study was to report the effects of transcranial direct current stimulation (tDCS) on countermovement jump (CMJ) performance in young healthy men. Seventeen healthy male subjects volunteered for the study (age: 22.4 ± 2.6 years; body mass: 71.8 ± 8.7 kg; height: 174.6 ± 5.9 cm; and CMJ height: 36.8 ± 6.3 cm). After a familiarization session, subjects underwent 3 experimental conditions, 7 days apart, in a randomized, double-blinded crossover design: anodal, cathodal, and sham tDCS. The stimulation was applied over the dorsolateral prefrontal cortex for 15 minutes. During experimental sessions, subjects completed a warm-up and 3 CMJ trials separated by 1 minute before and after each of the 3 experimental conditions. Countermovement jump height and muscular peak power were extracted from the best CMJ in each moment. A 2-way repeated-measures analysis of variance with time and condition as factors were performed for CMJ height and muscular peak power. Effect size analysis was conducted using Cohen's d coefficient. The analysis did not show either significant main effects or interactions for both time and condition factors in the CMJ performance (p > 0.05). Furthermore, effect size was trivial for all conditions (d: 0.01–0.14) in CMJ height and muscular peak power. These findings suggest that tDCS may not be a valuable tool to improve vertical jump performance.