Muscle fatigue can influence the various mechanisms that regulate balance. Few studies have investigated the effects of trunk extensor muscle fatigue on postural control. The purpose of this study was to evaluate the impact of trunk extensor fatigue during a one-leg balance test in young and elderly adults, as well as to determine the time necessary to recover posture control after fatigue. A total of 36 subjects (18 elderly and 18 young adults) participated in the study. Subjects were tested on a force platform to assess the postural control parameters associated with center of pressure (COP) movements, before and after a fatiguing trunk extension-flexion exercise on a roman chair carried out to exhaustion. Post-fatigue effects and postural control recovery were investigated at different times in minutes (MIN): immediately post-fatigue (postIME), after 5 (rec5MIN), 10 (rec10MIN), and 20 min (rec20MIN). Elderly subjects had greater sway (P < 0.05) than young adults in all COP parameters. In both groups, there was an increase in postIME sway compared with pre-fatigue values for all COP parameters. However, the differences were significant only for the COP velocity parameter, with more pronounced effects in young adults that did not return to pre-fatigue values at the end of rec20MIN. The present study demonstrated a significant effect of trunk extensor muscle fatigue on postural control, which was more evident in young adults than in the elderly.

No abstract

These results suggest that the inclusion of a single set of exhaustive exercise at 20 % of 1RM before traditional hypertrophic training can be a suitable strategy for inducing additional beneficial effects on quadriceps strength, hypertrophy, and endurance in young men.

Postural instability is a common problem among older people, and it is associated with mobility impairments, activity limitation and fear of falling. The evaluation of postural control can contribute to the early detection of balance deficits and help health professionals to manage this problem to prevent falls in older adults. The aim of this study was to identify center of pressure cut-offs to differentiate between older adults with and without falls in the past 12 months. The participants were 170 older adults (mean age 67 years, 50 fallers and 120 non-fallers). Center of pressure area and sway velocity in the anterior-posterior and medio-lateral directions were assessed using a force platform during three 30s one-legged stance trials with eyes open. The mean across trials was used for analysis. The time-limit (how long the participant was able to stay in one-legged stance, up to 30s) was also assessed. Fallers had poorer postural control than non-fallers (effect size ≥ 0.52, P <0.05). The cut-offs identified were 10.3 cm2 for Center of pressure area, 2.9 cm/s for velocity in the anterior-posterior, and 3.4 cm/s for medio-lateral velocity. The force platform parameters obtained an area under the curve of 0.72, with sensitivity of 78% and specificity of 68%. There were no significant differences between non-fallers and fallers for time-limit variable (17 seconds vs. 18 seconds). Force platform parameters during one-legged stance were associated with history of falls in older adults. The cut-offs obtained acceptable area under curve, sensitivity and specificity, with center of pressure area presenting the best performance to differentiate between fallers and non-fallers.

[Purpose] The aim of this study was to compare age-related differences in balance and anthropometric posture measurements of the foot and to determine any relationship between them. [Subjects and Methods] Sixty-eight older and 42 younger adults participated in this study. Foot posture was tested for four domains: 1) hallux flexion and extension range of motion using a goniometer, 2) navicular height and 3) length of the foot using a pachymeter, and 4) footprint (width of forefoot, arch index and hallux valgus). Balance was tested under two conditions on a force platform: bipodal in 60-s trials and unipodal in 30-s trials. The sway area of the center of pressure and velocity in the anteroposterior and mediolateral directions were computed. [Results] Older individuals showed significantly poorer balance compared with younger adults under in the unipodal condition (center of pressure area 9.97 vs. 7.72 cm2). Older people presented a significantly lower hallux mobility and higher values for width of the forefoot and transverse arch index than younger adults. The correlations between all foot posture and center of pressure parameters varied across groups, from weak to moderate (r −0.01 to −0.46). Low hallux mobility was significantly related to higher center of pressure values in older people. [Conclusion] These results have clinical implications for balance and foot posture assessments.

No abstract

| This study aimed to compare the postural balance of professional tae kwon do athletes with a non-tae kwon do adult group. Nineteen participants (nine tae kwon do practitioners and ten non-tae kwon do practitioners) were tested. To measure the postural sway, a force platform was used and the equipment recorded the main parameters: area of center of pressure; mean frequency, and velocity of center of pressure for both anteroposterior and mediolateral directions were measured for all participants. Before starting the assessment, the subjects received instructions and performed familiarization with the equipment and protocol. Participants were instructed to carry out three balance tests on a single-leg stance position with eyes opened. Values obtained in the postural assessment of professional athletes with the force platform were lower for all parameters compared to non-practitioners, except the frequency of center of pressure in the mediolateral direction. However, a significant difference (p=0.021) between the groups was found only in the center of pressure velocity parameter in the anteroposterior direction. These results have any implications on sport rehabilitation programs for balance assessments in athletes.Keywords | Martial Arts; Postural Balance; Athletes.Comparison of postural balance between professional tae kwon do athletes and young adults RESUMO | Este estudo teve como objetivo comparar o equilíbrio postural de atletas profissionais de tae kwon do com um grupo de adultos não praticantes do esporte. Dezenove participantes (nove praticantes profissionais de tae kwon do e dez não praticantes) foram testados. Para avaliar a oscilação postural, uma plataforma de força foi utilizada e o equipamento registrou os principais parâmetros: área do centro de pressão; frequência e velocidade do centro de pressão tanto para a direção anteroposterior, quanto para a médio-lateral. Essas medidas foram registradas para todos os participantes. Antes de iniciar a avaliação, os sujeitos receberam orientações e se familiarizaram com o equipamento e o protocolo. Também foram instruídos a realizar três testes de equilíbrio em apoio unipodal com os olhos abertos. Os valores obtidos na avaliação postural de atletas profissionais com o uso da plataforma de força foram inferiores para todos os parâmetros, quando comparados com aqueles dos não praticantes, com exceção da frequência do centro de pressão para a direção médio-lateral. No entanto, encontrou-se uma diferença significativa (p=0, 021) entre os grupos somente no parâmetro da velocidade anteroposterior do centro de pressão. Esses resultados apresentam implicações nos programas de reabilitação esportiva para avaliação do equilíbrio postural em atletas.Descritores | Artes Marciais; Equilíbrio Postural; Atletas.

Introduction: Rhythmic gymnastics requires a high level of physical quality; therefore, good performance depends on muscular strength and endurance, motor coordination and postural balance. Objective: Develop a comparative analysis of postural balance in rhythmic gymnasts. Methods: 10 rhythmic female gymnasts were evaluated on a force platform on one-foot and balance functional tests (Side Hop Test and Figure of Eight Hop Test). The anteroposterior and mediolateral of the center of pressure (COP) parameters were used for the functional tests, while for the functional tests, the performance time-seconds was analyzed. Results: Significant difference (p = 0.01) was found between lower limbs in the mean frequency parameter in the mediolateral direction, in which the non-dominant lower limb presented higher postural stability than the dominant one. For functional tests, there was no significant difference between limbs. Conclusion: The difference found in the control of balance of mediolateral direction may be related with different muscular actions of the hip region, which is present during the sport practice for stabilization, trunk maintenance and maneuvers performance with the lower limbs. These results indicate the need of a balance program and pelvic stabilization for the analyzed athletes in order to maintain muscular symmetry of the limbs for high sports performance.