Uphill Racewalking at Iso-Efficiency Speed

    loading  Checking for direct PDF access through Ovid

Abstract

Padulo, J, Annino, G, Tihanyi, J, Calcagno, G, Vando, S, Smith, L, Vernillo, G, La Torre, A, and D'Ottavio, S. Uphill racewalking at iso-efficiency speed. J Strength Cond Res 27(7): 1964–1973, 2013—The aim of this study was to investigate the effects of gradients (0, 2, and 7%) on biomechanical parameters during racewalking (RW) at iso-efficiency speed (IES). During the experiment, 12 high-level athletes performed at IES on different slopes. The parameters studied were surface muscular activity (EMG) of 5 muscles of the leg using Muscle Lab (Boscosystem); kinematic parameters were collected using a high-speed camera (210 Hz) analyzed with Dartfish 5.5Pro; and heart rate (HR) was monitored with a Cardio Polar. The results showed step length (SL), step frequency (SF), and internal work (WINT) decreased with increased treadmill gradient: SL = ([0–2% = 3.48%, p = 0.158], [0–7% = 12.17%, p < 0.001]); SF = ([0–2% = 2.38%, p = 0.173], [0–7% = 6.07%, p < 0.01]); WINT = ([0–2% = 8.34%, p < 0.001], [0–7% = 22.81%, p < 0.0001]). Conversely, contact time (CT) and HR increased less significantly with the increased gradients: CT = ([0–2% = 2.46%, p = 0.198], [0–7% = 6.56%, p < 0.01]); HR = ([0–2% = 0.62%, p = 0.652], [0–7% = 3.25%, p < 0.05]). The knee angle (KE) increased, whereas ankle angle (AK) and hip angle (HP) decreased with the increased gradients: AK = ([0–2% = 1.69%, p < 0.001], [0–7% = 1.13%, p < 0.01]); HP = ([0–2% = 0.22%, p < 0.03], [0–7% = 0.16%, p = 0.456]); KE = ([0–2% = 1.01%, p < 0.001], [0–7% = 1.60%, p < 0.001]). Electromyography (EMG) significantly decreased with the increased gradients in the: tibialis anterior ([0–2% = 22.49%, p < 0.0001], [0–7% = 41.18%, p < 0.0001]) and rectus femoris ([0–2% = 15.35%, p < 0.0001], [0–7% = 29.13%, p< 0.0001]). In contrast, EMG activity was significantly increased in the vastus lateralis ([0–2% = 22.95%, p < 0.0001], [0–7% = 31.15%, p < 0.0001]), gastrocnemius medialis ([0–2% = 21.40%, p < 0.001], [0–7% = 48.37%, p < 0.0001]), and biceps femoris ([0–2% = 190.78%, p < 0.0001], [0–7% = 201.37%, p < 0.0001]). The results indicate that increasing the gradient to 2% did not elicit an increased HR in racewalkers; however, at a 7% gradient, greater muscle activity was required.

Related Topics

    loading  Loading Related Articles