Muscle adaptations following 21 consecutive days of strength test familiarization compared with traditional training

INTRODUCTION: Large increases in 1-repetition maximum (1RM) strength have been demonstrated from repeated testing, but it is unknown whether these increases can be augmented by resistance training. METHODS: Five trained individuals performed a 1RM test and maximal voluntary isometric contraction (MVC) for unilateral elbow flexion exercise on 1 arm (testing arm), while the other arm performed a 1RM test and MVC, in addition to 3 sets of exercise (70% 1RM) (training arm), for 21 straight days. RESULTS: Although only the training arm had increased muscle thickness mean 0.28 cm, 95% confidence interval (CI) 0.22-0.33 cm, 1RM strength increased similarly in the training (2.2 kg, 95% CI 0.9-3.4 kg; P = 0.008) and testing (1.9 kg, 95% CI 0.5-3.2 kg; P = 0.019) arms. CONCLUSION: Increases in 1RM strength from resistance training are related to the specificity of exercise and are likely driven by mechanisms other than muscle growth. Muscle Nerve 56: 307-314, 2017.