EMG joint kinetics musculoskeletal model sprinting track and field ADHD Chronic pain Computational models Driftschätzung Elektromyographie Fortbewegung Kontrolle Locomotion Motor control Network models Neural network Schrittgeschwindigkeit Sensory afferents Silly walks Somatosensory system Spinal pattern generator Spinaler Mustergenerator Stabilität Walking speed Zeitreihenanalyse biomechanics children cognition curve sprinting evolution