Triceps Brachii Muscle Strength and Architectural Adaptations with Resistance Training Exercises at Short or Long Fascicle Length

The aim of this study was to investigate whether resistance training at short or long triceps brachii fascicle length induces different muscular strength and architectural adaptations. Nine young, novice, female participants, were trained for 6 weeks (two sessions/week) performing 6 sets × 6-RM (repetition maximum) unilateral cable exercises either with push-downs at short fascicle length (S) or overhead extensions with the contralateral arm at long fascicle length (L) of triceps brachii. Before and after training, 1-RM elbow extension and triceps brachii muscle architecture were evaluated. Muscle architecture was analyzed at 50% and 60% of the upper-arm length. Two-dimensional longitudinal muscle area of the triceps long head was also analyzed. The results indicated that 1-RM increased 40.1 ± 21.3% and 44.5 ± 20.1% (p < 0.01) after S and L, respectively. Muscle thickness at 50% length was increased 10.7 ± 15.3% (p < 0.05) and 13.7 ± 9.0% (p < 0.01) after S and L, while at 60% it was increased 15.5 ± 18.8% (p < 0.05) and 19.4 ± 16.3% (p < 0.01), respectively. Longitudinal muscle area increased similarly after S and L (p < 0.01). Fascicle angle and length were not altered with training. These results indicate that muscle strength and architecture of elbow extensors adapt similarly during the first six weeks of resistance training at either long or short fascicle length.