Determinants of Fatigue in the Biceps Brachii During Blood Flow Restriction Training

poster abstractTraining loads of 60% - 80% of maximum are traditionally recommended for increasing muscular strength. Lifting lighter loads (~20% of 1RM) with concomitant blood flow restriction (BFR) can also increase muscle strength. It is unknown if adaptation with BFR is limited to the muscle or also due to changes in the nervous system. We examined changes in the output of the motor cortex and the muscle with stimulation, when subjects perform 1.) Training with light loads, 2.) Training with light loads with BFR, and 3.) Training with moderate loads. 5 subjects completed three training sessions with the elbow flexor muscles. Maximal strength was measured before and after each training session. Voluntary activation was tested with cortical stimulation (TMS) and with electrical stimulation of the biceps during additional MVCs. Subjects trained with a block of 4 isometric contractions at 20% MVC (120s, 60s, 60s, 60s durations) or at 60% MVC (40s, 20s, 20s, 20s durations). Fatigue (% decrease in MVC after training) was similar between 20% with BFR and 60% conditions (18.6% and 16%) and less in the 20% without BFR condition (9.7%). Cortical voluntary activation decreased similarly between the 20% BFR and 60% conditions (-3.6% and -3.3%) and showed less change with 20% without BFR (-1.8%). Alternatively, with electrical stimulation of the muscle, both 20% training conditions showed a decline in voluntary activation (-3.1% and -5.15), while voluntary activation increased by 8% after the 60% condition. Similar levels of fatigue occur at different contraction intensities when BFR is applied during the lighter contraction. Both 20% with BFR and 60% loading causes deficits in cortical activation, though the limiting factor in the 20% BFR condition is a decrease in activation of the muscle directly, while in the 60% contraction it is due to an inability to drive the motorneuron pool sufficiently

Does Vibration Training Improve Physical Function and Quality of Life in Fibromyalgia Syndrome?

poster abstractExercise and physical activity recommendations are an integral component of the overall management of fibromyalgia. Unfortunately, despite the known health, fitness, and symptom relief benefits, underlying pain and fatigue prevent most from initiating (or maintaining) physical activity and exercise programs, thereby contributing to sedentary lifestyles that lead to low levels of aerobic and muscular fitness. Therefore, it is important to identify alternative approaches to exercise programming in the overall management of fibromyalgia. Vibration training is a relatively new approach to exercise that has been shown to elicit numerous benefits; however little is known about the effects of this training method in fibromyalgia. Therefore, the primary aim of this study is to evaluate the effects of vibration training in improving musculoskeletal function, balance and postural control, and health-related quality of life in patients diagnosed with fibromyalgia

The effect of music on body sway when standing in a moving virtual environment

Movement of the visual environment presented through virtual reality (VR) has been shown to invoke postural adjustments measured by increased body sway. The effect of auditory information on body sway seems to be dependent on context with sounds such as white noise, tones, and music being used to amplify or suppress sway. This study aims to show that music manipulated to match VR motion further increases body sway. Twenty-eight subjects stood on a force plate and experienced combinations of 3 visual conditions (VR translation in the AP direction at 0.1 Hz, no translation, and eyes closed) and 4 music conditions (Mozart's Jupiter Symphony modified to scale volume at 0.1 Hz and 0.25 Hz, unmodified music, and no music) Body sway was assessed by measuring center of pressure (COP) velocities and RMS. Cross-coherence between the body sway and the 0.1 Hz and 0.25 Hz stimuli was also determined. VR translations at 0.1 Hz matched with 0.1Hz shifts in music volume did not lead to more body sway than observed in the no music and unmodified music conditions. Researchers and clinicians may consider manipulating sound to enhance VR induced body sway, but findings from this study would not suggest using volume to do so

Floor composition affects performance and muscle fatigue following a basketball task

On compare la fatigue musculaire ressentie et objective (EMG) lors d'une tâche simulée de basket effectuée sur un sol en parquet ou sur un sol plus souple en matériaux composites