Objectives:This study examined the postural performance of two groups of male skiers competing at different levels and the consequences on postural control of the suppression of visual afferences by eye closure.Methods:Seven national level (NAT) skiers and 7 regional level (REG) skiers were asked to stand as still as possible on a force platform with eyes opened and closed and while wearing or not wearing their ski boots in a stable posture and in two unstable postures (in the sagittal or frontal plane). Postural performance was assessed with centre of foot pressure measurements.Results:REG and NAT skiers were similarly influenced by the absence of visual information and presented similar postural performance when tests were performed with ski boots. However, without ski boots, REG skiers displayed better postural performance than NAT skiers.Conclusions:The inferior postural performance of NAT skiers without ski boots could be a long term effect of repetitive wearing of ski boots, which impairs postural performance by restricting the range of motion of the ankle-foot complex. Since individuals with decreased postural performance are believed to be more susceptible to ankle injury than those with finer postural control, NAT skiers should benefit from specific training aimed at improving postural ability and preventing ankle injury.

The current literature shows no consensus regarding the difference between the dominant leg (D-Leg) and the non-dominant leg (ND-Leg) in terms of postural control. This lack of consensus could stem from motor experience (i.e., symmetric or asymmetric motricity) and/or the physiological state induced by physical exercise. This study aimed to investigate the acute effects of fatiguing exercise on postural control when standing on the D-Leg and the ND-Leg, in athletes practicing symmetric (SYM) and asymmetric (ASYM) sports. Thirty healthy male participants were recruited and divided into two groups, (SYM n = 15) and (ASYM n = 15, on the basis of the motricity induced by the sport they practice. Monopedal postural control was assessed for the D-Leg and the ND-Leg before and after the fatigue period (which consisted of repeating squats until exhaustion). A force platform was used to calculate the spatio-temporal characteristics of the displacements of the center of foot pressure (COP). A significant fatigue effect was observed in both groups on the D-Leg and the ND-Leg for all the COP parameters. There was a tendency (p = 0.06) between the ASYM and SYM groups on the D-Leg, concerning the relative increase in the COP velocity in the frontal plane after the fatigue period. The fatigue condition disturbed postural control in both the SYM and ASYM groups on the D-Leg and ND-Leg. This disturbing effect related to fatigue tends to be more marked in athletes practicing asymmetric sports than in athletes practicing symmetric sports on the D-Leg.

The aim of this study was to characterize daily fluctuations in postural control, gait and plantar cutaneous sensitivity in institutionalized older adults. Twenty-five older adults (>85 years old) living in a nursing home were recruited. Postural, gait and plantar cutaneous sensitivity parameters were collected at the following times: 8:00, 11:00, 14:00 and 17:00. Statistics were first calculated with the data from the whole group of the participants. A hierarchical cluster analysis was performed as a second step in order to determine if there was more than one pattern in the daily fluctuations of gait, postural control and plantar cutaneous sensitivity. When considering data from the whole group, results showed that postural control deteriorated from morning to the early afternoon and that gait improved from early to late morning. Daily fluctuations of plantar cutaneous sensitivity showed a decrease in tactile acuity in the afternoon. For most gait, postural control and plantar cutaneous sensitivity parameters, the hierarchical cluster analysis showed that there were three subgroups within the whole group of participants who had similar fluctuation patterns. Participants with the best tactile acuity, postural control and gait displayed relatively constant patterns without a period of increased risk of falling. By contrast, participants who presented a poor tactile acuity with a less efficient postural control and gait had greater daily fluctuations of plantar cutaneous sensitivity, with a marked decline of postural control and gait in the afternoon. In spite of a strong relationship between plantar cutaneous sensitivity and gait/postural control, the decline in postural control and gait observed in the afternoon could not be related to plantar sensation. It might rather relate to a cognitive function which is known to peak early in human circadian rhythms and to have a greater contribution in postural control regulation in the elderly than in young healthy subjects.

There is controversy about the influence of compression garments on balance control. A positive influence was reported in elderly and injured individuals, whereas no beneficial effects were observed in young healthy active subjects, which is likely due to the large inter-individual differences in these subjects. Hence, this study investigated the acute effects of compression garments on balance control in young healthy active subjects by addressing the issue of heterogeneity of individuals’ responses to the wearing of compression garments. Thirteen young, healthy, active subjects were recruited. They stood on a force plate which recorded the center of foot pressure displacements in a monopedal stance with the eyes closed and on a wobble board with the eyes open, while wearing compression garments or not. Statistics were first calculated with the data from the whole sample. A hierarchical cluster analysis was also performed in order to categorize the participants’ behaviors into subgroups with similar characteristics. The whole group analysis showed that there were no significant effects attributed to compression garments. The clustering analysis identified distinct and homogeneous subgroups of participants. Only participants who swayed the more at baseline benefited from the wearing of compression garments to improve their balance control. These participants might have either a gravity-dependent preferred sensorimotor strategy with an exploratory postural behavior or poorer balance/proprioceptive abilities. Since poor balance control is a predictor of sports injury risk, wearing compression garments during sports practice could be viewed as a potential prevention strategy for individuals at risk.