Abstract

Functional adaptations in human skeletal muscle following a period of resistance exercise are the result of regular activation of cellular signaling pathways that elevate muscle protein synthesis. It has been reported that the addition of whole body vibration (WBV) to a resistance exercise program enhances performance. Such improvements in muscle function may be the result of increased activation of cellular signaling pathways associated with muscle growth. Purpose: We have investigated whether an acute bout of resistance exercise in combination with WBV results in a greater activation of the mTOR signaling pathway compared to resistance exercise alone. Methods: Eight untrained college-age males (23 ± 2 yrs, 179 ± 1 cm, 75.0 ± 2.5 kg, and 12.6 ± 1.8% body fat) performed unilateral leg press exercises with (Vbx) and without (RT) vibration. Muscle samples were obtained from the vastus lateralis muscle pre-exercise (baseline) and one-hour following the bout of resistance exercise. Muscle tissue samples were analyzed for phosphorylated levels of mTOR, p70S6K, and 4E-BP1 proteins. Results: One-hour following the resistance exercise bout there were no differences between phosphorylated levels of mTOR or 4E-BP1 in Vbx or RT (p > 0.05). Levels of phosphorylated p70S6K were increased at the one-hour post-exercise time-point in both Vbx (baseline: 504 ± 286 OD; post: 5039 ± 2351 OD, p < 0.05) and RT (baseline: 356 ± 131 OD; post: 5430 ± 1218 OD, p < 0.05); however, there was no difference in protein phosphorylation levels between conditions (p > 0.05). Conclusion: Vibration does not augment acute activation of the mTOR signaling pathway in human skeletal muscle suggesting that performance benefits resulting from combining resistance exercise and vibration may not be the result of an enhanced cellular growth response.

Degree

College and Department

Life Sciences; Exercise Sciences

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