Metabolic and electromechanical investigation during individual stimulated muscle exertion and volitional systemic adapted physical activity

Our research has analysed various possible aspects that are essential to define custom programs of Adapted Physical Activity; there are many tools that allow performing various types of assessments and obviously not everyone could be considered. Therefore the first study was aimed to provide a novel objective method to measure the degree of individual muscle oxygen supply/uptake balance during exertion through a controlled incremental activation of the motor unit (MU) pool through neuromuscular electrical stimulation (NMES) that is independent from motivation and central control of tested subjects. This tool could be applied to estimate the kinetics of aerobic adaptation to increasing metabolic demand in muscles affected by myopathies or subjected to rehabilitation or training programmes. Afterwards we have moved from local to global measures, studying different kinds of APA in a rehabilitation setting. In second and fourth study we treat two different special leisure time physical activities for SCI subjects. In particular, energy expenditure and metabolic adaptation during activity promoting video games (APVG) and during handbike exercise on a specific designed ergometer. At the end, in the research, we investigated a typical post stroke rehabilitation treatment, such as BWS, studying the influence of body weight reduction and walking speed on energy expenditure and lower limb muscles recruitment. Summarizing the four studies were: 1. Oxygen supply/uptake mismatch during incremental stimulation of human tibialis anterior. 2. Energy expenditure of activity-promoting video games in spinal cord injured subjects. 3. Physiological Cost Index and Muscular Recruitment during Body Weight Support Treadmill Training in Healthy and Stroke Patients 4. Metabolic evaluation of the disabled athlete during handcycling on a specific designed ergometer: preliminary results Conclusions of the four studies were: 1. Our work provided a relatively simple tool for the objective functional evaluation of the O2 supply/uptake balance, independent of subject motivation, in a single skeletal muscle in humans at increasing levels of output force. In particular its sensitivity showed that the higher the O2Hb concentration at rest, the better is the specific behaviour of the microvascular network response, with incremental stimulation, in limiting O2M. Indeed, Fig. 2.3 clearly shows that the higher the fatigability of the stimulated muscle, the higher the O2M area. This fact may be related to the degree of inadequacy of the microcirculation to match the increased O2 demand from one level of the evoked contractions to the next, more intense, level with more O2Hb to be deoxygenated to HHb. This tool could be applied to estimate the kinetics of aerobic adaptation during transients of increasing metabolic demand in muscles affected by specific myopathies or the effects of particular rehabilitation protocols, treatments and/or training programmes. 2. This work suggests that in spinal cord injured subjects APVG practice induces sizeable increases of cardiopulmonary and metabolic parameters. The related functional adaptations, especially for boxing, may be considered an aerobic training stimulus to promote health. Furthermore, the energy expenditure increase may play a role in total energy balance computation when subject weight control is sought for. 3. Body weight support treadmill training in healthy or post stroke subjects is well tolerated. This practice enables post stroke patients to have longer and more effective training session with a lower physiological cost index. This last and VO2 are strongly correlated so, the PCI can be evaluated inexpensively in a clinical setting, to get exercise capacity on treadmill and compare two or more patients. The best EMGTOT / PCI value significance requires further analysis. A longitudinal study will be suitable to check if the suggested combination of speed and BWR will be the most favourable to reach a valuable muscular and aerobic training stimuli to retain post stroke patient. 4. These preliminary results introduced a new instrumented handbike which will help to control handcycling intensity. A successful integration of aerobic exercise training into rehabilitation protocol of people with Spinal Cord Injury may be more likely if aerobic exercise is safe, easily adjustable to a low physical capacity subject, fun to do, motivating, and useful in daily mobility. Handbike practice may meet these requirements. Important features of this ergometer are an adequate ergonomic interface and an optimal system to impose a precise power exertion. A system that allows training and testing with the same device, may be a useful tools in helping Adapted Physical Activity operators to plan specific physical activity programs. Further studies need to be conducted with similar but larger populations.