Determining optimal exercise dose for the biceps femoris in rehabilitation training of sacro-iliac pain patients.
A link between sacro-iliac (SI) type pain and alterations in biceps femoris recruitment affecting lumbopelvic stability has been widely described. In TMG100 tensiomyography assessments of patients with SI complaints it is common to find significant bilateral differences in biceps femoris contraction properties. Most often the biceps femoris on the affected side will have a longer contraction time (Tc) than on the opposite side. This suggests that, during walking and running, the affected muscle produces its peak power later than on the opposite side potentially placing excessive stresses on the SI joint.
It is common practice to prescribe activation exercises to acutely and chronically decrease contraction time, with the aim to firstly increase fast motor unit activation and secondly to increase the fast fiber type ratio in the biceps femoris. During therapeutic exercise and rehabilitation training it is important to avoid excessive local muscle fatigue since this would only further increase the functional imbalance between both biceps femoris muscles, thus leading to a further deterioration of lumbopelvic stability and possible onset of discomfort.
In order to define the appropriate dose of exercises, i.e. number of repetitions and sets, TMG100 is used to monitor the muscle's response to the activation exercise. After each short set of repetitions TMG100 parameters are checked; a decrease in contraction time and increase in radial displacement suggest muscle potentiation, while an increase in contraction time and decrease in radial displacement suggest local muscle fatigue. When the latter is detected during this simple test, we can determine the dose of exercise that can be done before local muscle fatigue sets in, safeguarding the positive effects of rehabilitation training on lumbopelvic stability. TMG100 tensiomyography can also be used to monitor resting contraction times before each rehabilitation session; decreases in contraction time suggest chronic changes in muscle fibre type ratios towards fast fibre types, which should contribute to improvements in lumbopelvic stability in the long term. In these cases TMG100 tensiomyography not only provides deeper insights into possible disorder mechanisms, but it also serves as a tool to monitor the effects of rehabilitation training on specific muscles so that training programmes and schedules can be optimized for higher efficacy and efficiency in rehabilitation trainnig.
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