Proper positioning of the scapula during upper extremity movement is crucial for the maintenance of joint function and health, optimal muscle lengths, force production, and bony and soft tissue alignment [ 1].
This ratio apparently gives optimal timing between muscle force and extension.
Once the maximal stimulus intensity and optimal muscle length (Lo) for force production were determined (at 50 Hz and train of 500 milliseconds), peak twitch tension (Ptw), time-to-peak twitch tension (TPT) and RT½ (the time for Ptw to relax to one-half Ptw) were determined at Lo from a series of contractions induced by single-pulse stimuli.
Elicited twitch contractions were utilized to determine the optimal stimulus amplitude (Vo) and optimal muscle length (Lo) for isometric force production in the EDL muscle.
Contractile measurements were taken at the optimal muscle length (Lo), the length at which maximal force is obtained.
The model is composed of four sub-models that comprise a mathematical as well as graphical three-dimensional representation of the upper extremity: a musculoskeletal model for estimation of muscle tendon lengths and moment arms, a Hill-based muscle force model, a model for estimating optimal muscle lengths, and a model for estimation of muscle activation from EMG signal of the biceps.
The scapula acts as a stable base for optimal muscle activation and as a transfer link for developed forces in the kinetic chain [ 1].
As either an increase or a reduction in ROS levels determined a reduction in muscle force, they suggested that there was an optimal redox state for force production [ 40].
It is possible that a different vibration magnitude is needed for optimal muscle adaptations, and in fact, many other studies have used higher g forces with success for such outcomes [ 2, 32, 33].
Different authors used different criteria to determine optimal cylindrical handle: subjective comfort rating [ 14, 15], finger force measurement [ 16, 17], muscle force minimization [ 18], and hand anthropometrics [ 14, 19– 24].
