Spontaneous change from seated to standing cycling position with increasing power is associated with a minimization of cost functions.

Spontaneous changes of movement patterns may allow to elucidate which criteria influence movement pattern preferences. However, the factors explaining the sit-stand transition in cycling are unclear. This study investigated if biomechanical and/or muscle activation cost functions could predict the power at which the spontaneous sit-stand transition occurs.

Threshold position control of anticipation in humans: a possible role of corticospinal influences.

Key Points: Sudden unloading of preloaded wrist muscles elicits motion to a new wrist position. Such motion is prevented if subjects unload muscles using the contralateral arm (self-unloading). Corticospinal influences originated from the primary motor cortex maintain tonic influences on motoneurons of wrist muscles before sudden unloading but modify these influences prior to the onset and until the end of self-unloading.

Can muscle coordination explain the advantage of using the standing position during intense cycling?

Objectives: When compared to seated, the standing position allows the production of higher power outputs during intense cycling. We hypothesized that muscle coordination could explain this advantage. To test this hypothesis, we assessed muscle activity over a wide range of power outputs for both seated and standing cycling positions.

Upper limb and trunk muscle activity patterns during seated and standing cycling.

The objective of this study is to clarify the functional roles of upper limb muscles during standing and seated cycling when power output increases. We investigated the activity of seven upper limb and trunk muscles using surface electromyography (EMG). Power outputs ranged from ~100-700 W with a pedalling frequency of 90 revolution per minute.

A reduction of the saddle vertical force triggers the sit-stand transition in cycling.

The purpose of the study was to establish the link between the saddle vertical force and its determinants in order to establish the strategies that could trigger the sit-stand transition. We hypothesized that the minimum saddle vertical force would be a critical parameter influencing the sit-stand transition during cycling. Twenty-five non-cyclists were asked to pedal at six different power outputs from 20% (1.

Corticospinal control strategies underlying voluntary and involuntary wrist movements.

The difference between voluntary and involuntary motor actions has been recognized since ancient times, but the nature of this difference remains unclear. We compared corticospinal influences at wrist positions established before and after voluntary motion with those established before and after involuntary motion elicited by sudden removal of a load (the unloading reflex). To minimize the effect of motoneuronal excitability on the evaluation of corticospinal influences, motor potentials from transcranial magnetic stimulation of the wrist motor cortex area were evoked during an EMG silent period produced by brief muscle shortening.