Acute Effects within 5 Days of Daily Whole-Body Vibration Training on Leg Muscle Activity, Heart Rate, Blood Pressure, Lactate, and IGF-1

Kurzfassung

Acute effects within 5 days of daily whole-body vibration training on leg muscle activity, heart rate, blood pressure, lactate and IGF-1 Rosenberger, A.(1,2), Bargmann, A.(1,3), Müller, K.(1), Beck, L.(1), Liphardt, A-M.(1,2), Mester, J.(2), Zange, J.(1,3) 1: German Aerospace Center (Cologne, Germany), 2: German Sport University Cologne (Cologne, Germany), 3: University of Cologne (Cologne, Germany) Introduction Whole-body vibration training (WBVT) has become a popular method in recreational and athletic training and rehabilitation medicine. Acute effects of WBVT as well as long term effects of WBVT have intensively been studied in recent years (for review see Rittweger, 2010). However, little is known about the changes in the acute effects of WBVT on muscle activity and autonomic functions during the initial days of a daily training. We tested the hypothesis that WBVT during slow squats in comparison to mere squats (conventional resistive training, CRT) causes excess muscular activity and cardiovascular reactions over 5 days of daily training. Methods Electromyography (EMG) was recorded on the m. rectus femoris and the m. gastrocnemius lateralis. Electrocardiogram (ECG) and continuous finger blood pressure was recorded using a separate data acquisition system (BIOPAC-Systems, Goleta, CA, USA). Results On day 1, EMG amplitudes in m. rectus femoris were higher by 36% during WBVT than during CRT. This difference was reduced to insignificantly different levels on day 5. During WBVT, the increase in heart rate (HR) was 15 beats per minute higher than during CRT on day 1. This difference declined and was not significant anymore on days 4 and 5. Net lactate formation was the highest on day 1 (3.8±2.6 mmol/l in WBVT vs. 1.2±1.9 mmol/l in CRT). On the following days, these differences declined, but still reached statistical significance. Morning and post training levels of IGF-1 were not altered by WBVT and CRT. Discussion In most variables, excess effects of WBVT over CRT were largest on the initial day of training and declined to insignificant levels within following days. The higher initial values of the EMG, HR and lactate were expected because vibration training is an additional stress for the human body (Rittweger et al., 2003; Torvinen et al., 2002). Furthermore, WBVT was a new experience for all subjects and needed a more conscious execution of the squats which may have led to worse coordinated and less efficient squats at the beginning of the vibration training. However, the decreasing EMG amplitudes showed a rapid adaptation, also to the additional vibration stimulus, on the neuromuscular level after 5 days of daily training. References Rittweger J (2010). Eur J Appl Physiol, 108, 877-904. Rittweger J, Mutschelknauss M, Felsenberg D (2003). Clin Physiol & Func Im, 23, 81-86. Torvinen S, Kannu P, Sievanen H, Jarvinen TA, Pasanen M, Kontulainen S, Jarvinen TL, Jarvinen M, Oja P, Vuori I (2002). Clin Physiol & Func Im, 22, 145-152.