Search

Low back pain (LBP) obviously reduces the quality of life but is also the world's leading cause of years lived with disability. Alterations in motor response and changes in movement patterns are expected in LBP patients when compared to healthy people. Such changes in dynamics may be assessed by the nonlinear analysis of kinematical time series recorded from one patient's motion. Since sample entropy (SampEn) has emerged as a relevant index measuring the complexity of a given time series, we propose the development of a clinical test based on SampEn of a time series recorded by a wearable inertial measurement unit for repeated bending and returns (b and r) of the trunk. Twenty-three healthy participants were asked to perform, in random order, 50 repetitions of this movement by touching a stool and another 50 repetitions by touching a box on the floor. The angular amplitude of the b and r movement and the sample entropy of the three components of the angular velocity and acceleration were computed. We showed that the repetitive b and r "touch the stool" test could indeed be the basis of a clinical test for the evaluation of low-back-pain patients, with an optimal duration of 70 s, acceptable in daily clinical practice. 24;4

International audience; Prolonged mountain biking can involve pain complain in the wrists due to the ulnar nerve compression when using traditional grips (Capitani et al., 2002; Eckman et al., 1975). This phenomenon seems to be amplified by mechanical vibrations that are largely encountered during MTB practice despite the use of damping systems located in the fork and/or the frame. Recently, SPIRGRIPS® (SG) have been designed to correct the position of the hands of the user naturally by aligning the joints of his forearms correctly which is not the case with traditional grips. The aim of this experimental study was to evaluate the effect of SG on transmissibility of mechanical vibrations, perceived comfort, muscular activity and hand grip force during a prolonged pedalling exercise.

A crossover experiment was performed to determine whether age and sex, or their interaction, affect the impact of acute aerobic exercise on Vigor-Activity (VA). We also tested whether changes in VA mediated exercise effects on performance on various cognitive tasks. Sixty eight physically inactive volunteers participated in exercise and TV-watching control conditions. They completed the Vigor-Activity subscale of the Profile of Mood States immediately prior to and 2 minutes after the intervention in each condition. They also performed the Trail Making Test 3 minutes after the intervention in each condition. Statistical analyses produced a condition × age × sex interaction characterized by a higher mean VA 10 gain value in the exercise condition (compared to the VA gain value in the TV-watching condition) for young female participants only. In addition, the mediational analyses revealed that changes in VA fully mediated the effects of exercise on TMT-Part A performance.

It is now well known that swimming drafting leads to a reduction in energy spent to overcome drag forces (friction, wave and pressure) and enhances gains time in competitive swimming (Chatard et al...

The aim of this study was to compare the maximal power output (POpeak) and force-velocity relationships in sprint cycling obtained from a laboratory protocol and from a field test during actual cycling locomotion.Seven male competitive cyclists performed 6 sprints (3 in the seated position and 3 in the standing position) on an ergo-trainer (Tacx, Netherlands) and 6 sprints during actual cycling locomotion in a gymnasium. The bicycle was equipped with the SRM Training System (Schoberer Rad Messtechnik, Germany) to measure (200 Hz) the power output (PO, W), the pedalling cadence (rpm), and the velocity (kmxh-1). From these measurements, the maximal force on the pedal (Fmax), the theoretical maximal force (Fo, N) and the theoretical maximal pedalling cadence (V0, rpm) were determined. During each sprint test the lateral bicycle oscillations were measured from a video analysis.During standing and seated sprints in the gymnasium, Fo and Fmax were significantly higher (p0.05) compared with sprints on the ergo-trainer (+12% and +32%, respectively). The POpeak during sprints in seated and standing positions in the gymnasium was significantly (p0.05) lower (-4%) and higher (+6%) respectively, compared with the ergo-trainer. For standing position in the gymnasium the kinematics analysis indicated a 24 degrees mean lateral bicycle oscillation compared with 0 degrees on the ergo trainer.The results of this study indicate that POpeak, Fo, and time to obtain POpeak were different between laboratory and actual cycling conditions. To obtain a valid estimation of the maximal power output, it is necessary to perform sprint tests during actual cycling locomotion. Thus, in the laboratory, it is advisable to use a cycle ergometer that enables natural lateral oscillations.