ABSTRACT
Background: The triceps surae muscle plays important roles in fundamental human movements. However, this muscle is relatively unresponsive to resistance training (difficult to hypertrophy) but prone to atrophy with inactivity compared with other muscles. Thus, identifying an effective training modality for the triceps surae is warranted. This study compared triceps surae muscle hypertrophy after standing/knee-extended versus seated/knee-flexed plantarflexion (calf-raise) training, where the gastrocnemius is lengthened and shortened, respectively. Methods: Fourteen untrained adults conducted calf-raise training with one leg in a standing/knee-extended position and the other leg in a seated/knee 90°-flexed position at 70% of one-repetition maximum. Each leg performed 10 repetitions/set, 5 sets/session, 2 sessions/week for 12 weeks. Before and after the intervention, magnetic resonance imaging scans were obtained to assess muscle volume of each and the whole triceps surae. Results: Muscle volume significantly increased in all three muscles and the whole triceps surae for both legs (p ≤ 0.031), except for the gastrocnemius muscles of the seated condition leg (p = 0.147-0.508). The changes in muscle volume were significantly greater for the standing than seated condition leg in the lateral gastrocnemius (12.4% vs. 1.7%), medial gastrocnemius (9.2% vs. 0.6%), and whole triceps surae (5.6% vs. 2.1%) (p ≤ 0.011), but similar between legs in the soleus (2.1% vs. 2.9%, p = 0.410). Conclusion: Standing calf-raise was by far more effective, therefore recommended, than seated calf-raise for inducing muscle hypertrophy of the gastrocnemius and consequently the whole triceps surae. This result and similar between-condition hypertrophy in the soleus collectively suggest that training at long muscle lengths promotes muscle hypertrophy.
ABSTRACT
BACKGROUND: As an adjunct to running training, heavy resistance and plyometric training have recently drawn attention as potential training modalities that improve running economy and running time trial performance. However, the comparative effectiveness is unknown. The present systematic review and meta-analysis aimed to determine if there are different effects of heavy resistance training versus plyometric training as an adjunct to running training on running economy and running time trial performance in long-distance runners. METHODS: Electronic databases of PubMed, Web of Science, and SPORTDiscus were searched. Twenty-two studies completely satisfied the selection criteria. Data on running economy and running time trial performance were extracted for the meta-analysis. Subgroup analyses were performed with selected potential moderators. RESULTS: The pooled effect size for running economy in heavy resistance training was greater (g = - 0.32 [95% confidence intervals [CIs] - 0.55 to - 0.10]: effect size = small) than that in plyometric training (g = -0.13 [95% CIs - 0.47 to 0.21]: trivial). The effect on running time trial performance was also larger in heavy resistance training (g = - 0.24 [95% CIs - 1.04 to - 0.55]: small) than that in plyometric training (g = - 0.17 [95% CIs - 0.27 to - 0.06]: trivial). Heavy resistance training with nearly maximal loads (≥ 90% of 1 repetition maximum [1RM], g = - 0.31 [95% CIs - 0.61 to - 0.02]: small) provided greater effects than those with lower loads (< 90% 1RM, g = - 0.17 [95% CIs - 1.05 to 0.70]: trivial). Greater effects were evident when training was performed for a longer period in both heavy resistance (10-14 weeks, g = - 0.45 [95% CIs - 0.83 to - 0.08]: small vs. 6-8 weeks, g = - 0.21 [95% CIs - 0.56 to 0.15]: small) and plyometric training (8-10 weeks, g = 0.26 [95% CIs - 0.67 to 0.15]: small vs. 4-6 weeks, g = - 0.06 [95% CIs 0.67 to 0.55]: trivial). CONCLUSIONS: Heavy resistance training, especially with nearly maximal loads, may be superior to plyometric training in improving running economy and running time trial performance. In addition, running economy appears to be improved better when training is performed for a longer period in both heavy resistance and plyometric training.
