[Stress on adolescents due to forced positions in various postural loads]

To assess the strain imposed by defined static loads, eleven young males were studied in four different postures at three different loads held. In addition to the usual cardiovascular parameters of heart rate and arterial blood pressure, the long-term variability of the cardiac cycle (sinus arrhythmia) and the subjective exertion assessment according to Borg were used as strain criteria. Despite a high interindividual variability, HR arrhythmia data reflect in very good terms the strain imposed by predominantly central activation at static loads and forced postures. Such a strain assessment does not replace other modes of assessment such as biomechanical model considerations. Still, it may add to an assessment made on the basis of heart rate and blood pressure.