The authors investigated anticipatory postural adjustments in persons with unilateral stroke using external perturbations. Nine individuals with stroke and five control subjects participated. The electromyographic activity of 16 leg and trunk muscles was recorded. The onsets of muscle activity during the anticipatory phase of postural control were analyzed. The individuals with stroke did not show an anticipatory activation of leg and trunk muscles on the affected side; instead, the muscle onsets were seen after the perturbation, during the balance restoration phase. However, an anticipatory activation of muscles on the unaffected side was seen in individuals with stroke, and it was observed earlier compared with healthy controls (p < .05). The individuals with stroke showed a distal to proximal order of anticipatory activation of muscles on the unaffected side. The outcome of the study provides a basis for future investigations regarding ways of improving balance control in people with stroke.
Etem Curuk, Yunju Lee and Alexander S. Aruin
Mohan Ganesan, Yun-Ju Lee and Alexander S. Aruin
The use of a footrest while performing activity in standing is frequently associated with improvement of a user’s well-being however no information exists on the role of a footrest in improving postural stability. The aim of the study was to evaluate the effects of using a footrest in postural control. Twenty healthy young volunteers were tested using three experimental conditions: standing with two feet on the force platform and standing on the force platform when one foot was placed on a 15 cm footrest positioned in front or laterally. The mean and root mean square distance, range and velocity of the center of pressure (COP) were calculated in the anterior-posterior (AP) and medio-lateral (ML) directions using the force platform data. The COP displacements in AP and ML directions increased in conditions of standing with one foot placed on the footrest regardless of its location. Standing with eyes closed increased COP displacements further. The outcome of the study suggests the importance of using COP measures for evaluation of postural stability and provides additional information needed for optimization of working conditions involving standing with a footrest.
Leyre Gravina, Frankie F. Brown, Lee Alexander, James Dick, Gordon Bell, Oliver C. Witard and Stuart D.R. Galloway
Omega-3 fatty acid (n-3 FA) supplementation could promote adaptation to soccer-specific training. We examined the impact of a 4-week period of n-3 FA supplementation during training on adaptations in 1RM knee extensor strength, 20-m sprint speed, vertical jump power, and anaerobic endurance capacity (Yo-Yo test) in competitive soccer players. Twenty six soccer players were randomly assigned to one of two groups: n-3 FA supplementation (n-3 FA; n = 13) or placebo (n = 13). Both groups performed two experimental trial days. Assessments of physical function and respiratory function were conducted pre (PRE) and post (POST) supplementation. Training session intensity, competitive games and nutritional intake were monitored during the 4-week period. No differences were observed in respiratory measurements (FEV1, FVC) between groups. No main effect of treatment was observed for 1RM knee extensor strength, explosive leg power, or 20 m sprint performance, but strength improved as a result of the training period in both groups (p < .05). Yo-Yo test distance improved with training in the n-3 FA group only (p < .01). The mean difference (95% CI) in Yo-Yo test distance completed from PRE to POST was 203 (66–340) m for n-3 FA, and 62 (-94–217) m for placebo, with a moderate effect size (Cohen’s d of 0.52). We conclude that 4 weeks of n-3 FA supplementation does not improve strength, power or speed assessments in competitive soccer players. However, the increase in anaerobic endurance capacity evident only in the n-3 FA treatment group suggests an interaction that requires further study.