We compared running mechanics parameters determined from ground reaction force (GRF) measurements with estimated forces obtained from double differentiation of kinematic (K) data from motion analysis in a broad spectrum of running speeds (1.94–5.56 m⋅s–1). Data were collected through a force-instrumented treadmill and compared at different sampling frequencies (900 and 300 Hz for GRF, 300 and 100 Hz for K). Vertical force peak, shape, and impulse were similar between K methods and GRF. Contact time, flight time, and vertical stiffness (kvert) obtained from K showed the same trend as GRF with differences < 5%, whereas leg stiffness (kleg) was not correctly computed by kinematics. The results revealed that the main vertical GRF parameters can be computed by the double differentiation of the body center of mass properly calculated by motion analysis. The present model provides an alternative accessible method for determining temporal and kinetic parameters of running without an instrumented treadmill.
Gaspare Pavei, Elena Seminati, Jorge L.L. Storniolo and Leonardo A. Peyré-Tartaruga
Lorenzo Pugliese, Simone Porcelli, Matteo Bonato, Gaspare Pavei, Antonio La Torre, Martina A. Maggioni, Giuseppe Bellistri and Mauro Marzorati
Recently, some studies have suggested that overall training intensity may be more important than training volume for improving swimming performance. However, those studies focused on very young subjects, and/or the difference between high-volume and high-intensity training was blurred. The aim of this study was to investigate in masters swimmers the effects of manipulation of training volume and intensity on performance and physiological variables.
A group of 10 male masters swimmers (age 32.3 ± 5.1 y) performed 2 different 6-wk training periods followed by 1 wk of tapering. The first period was characterized by high training volume performed at low intensity (HvLi), whereas the second period was characterized by low training volume performed at high intensity (LvHi). Peak oxygen consumption (V̇O2peak) during incremental arm exercise, individual anaerobic threshold (IAT), and 100-m, 400-m, and 2000-m-freestyle time were evaluated before and at the end of both training periods.
HvLi training significant increased V̇O2peak (11.9% ± 4.9% [mean change ± 90%CL], P = .002) and performance in the 400-m (–2.8% ± 1.8%, P = .002) and 2000-m (–3.4% ± 2.9%, P = .025), with a likely change in IAT (4.9% ± 4.7%, P > .05). After LvHi training, speed at IAT (12.4% ± 5.3%, P = .004) and 100-m performance (–1.2% ± 0.8%, P = .001) also improved, without any significant changes in V̇O2peak, 2000-m, and 400-m.
These findings indicate that in masters swimmers an increase of training volume may lead to an improvement of V̇O2peak and middle- to long-distance performance. However, a subsequent period of LvHi training maintains previous adjustments and positively affects anaerobic threshold and short-distance performance.