Neuromuscular Fatigue Following Isometric Contractions with Similar Torque Time Integral

2014

International audience; Torque time integral (TTI) is the combination of intensity and duration of a contraction. The aim of this study was to compare neuromuscular alterations following different isometric sub-maximal contractions of the knee extensor muscles but with similar TTI. Sixteen participants performed 3 sustained contractions at different intensities (25 %, 50 %, and 75 % of Maximal Voluntary Contraction (MVC) torque) with different durations (68.5 +/- 33.4 s, 35.1 +/- 16.8 s and 24.8 +/- 12.9 s, respectively) but similar TTI value. MVC torque, maximal voluntary activation level (VAL), M-wave characteristics and potentiated doublet amplitude were assessed before and immediately a…

''Limits in endurance performance of octogenarian athletes''

2013

TO THE EDITOR: A recent study of Trappe et al. (3) showed that the aerobic power of octogenarian lifelong endurance athletes was approximately double that of untrained octogenarians (38 vs. 21 ml·kg 1 ·min 1 ). These remarkable aerobic capacities are the highest ever recorded in this age group. However, the impact of the identified physiological capacities on actual endurance performances has not been addressed, as no running performance indicators of the octogenarian athletes were provided in this study. We hereby suggest that, although trained octogenarian athletes can achieve levels of aerobic fitness well above their untrained counterpart, as a group they actually have not yet reached t…

What are the effects of the aging of the neuromuscular system on postural stability?

2015

International audience; Aging is frequently associated with a decreased postural stability, essentially after 60 years, leading to an increased risk of falling. In this article we propose to highlight the influence of the aging of the neuromuscular system on postural stability when standing upright. To maintain balance while standing upright, human needs to control the activity of ankle muscles and particularly the plantar flexors. During the aging process, the performance of these muscles are strongly altered. It is commonly observed large deficits in elderly people with history of falls. Some authors reported an inverse correlation between the amplitude of postural sway and the capacity o…

The involvement of ankle muscles in maintaining balance in the upright posture is higher in elderly fallers

2016

International audience; The purpose of this study was to determine whether the mechanical contribution of ankle muscles in the upright stance differed among young adults (YA) (n = 10, age: similar to 24.3), elderly non-fallers (ENF) (n = 12, age: similar to 77.3) and elderly fallers (EF) (n = 20, age: similar to 80.7). Torque and electromyographic (EMG) activity were recorded on the triceps surae and tibialis anterior during maximum and submaximum contractions in the seated position. EMG activity was also recorded in subjects standing still. Plantar flexor (PF) and dorsal flexor (DF) torques generated in the upright posture were estimated from the torque-EMG relationship obtained during sub…

La force des muscles mobilisateurs de la cheville est-elle prédictive du risque de chute ?

2012

Are Female Performances in Other Olympic Distance Running Events Equivalent to Paula Radcliffe's?

2015