Triceps surae muscle hypertrophy is greater after standing versus seated calf-raise training

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.

Keywords: bi- and monoarticular muscles; muscle length; muscle volume; resistance training; selective hypertrophy.

FIGURE 1

Postures of the standing and seated calf-raise exercises and operating ranges of each triceps surae muscle on the normalized force–length curve during the exercises. These were obtained using the OpenSim Gait 2392 model (Delp et al., 2007), with the knee joint 0° and 90° for the standing and seated conditions, respectively, and the ankle joint angle ranging from 20° dorsiflexed to 30° plantarflexed positions for both conditions. It can be clearly seen that the lateral and medial gastrocnemius (LG and MG) operate at longer muscle lengths in the standing than seated condition, while there is no difference between the conditions in the soleus (SOL).

FIGURE 2

Pictures of standing (A) and seated (B) calf-raise training, targeting the left and right leg, respectively.

FIGURE 3

Muscle volume before and after the training and its change. In each subfigure/muscle(s), the raw data is plotted on the upper axes for the standing (A) and seated (B) conditions; each paired set of observations at Pre and Post is connected by a line. On the lower axes, each paired mean difference is plotted as a bootstrap sampling distribution. Mean differences are depicted as dots with horizontal dashed lines; 95% confidence intervals are indicated by the ends of the vertical error bars. ***p < 0.001, **p < 0.01 and *p < 0.05 difference between times (pre vs. post). ##p < 0.01 and #p < 0.05 difference between conditions (legs). LG, lateral gastrocnemius; MG, medial gastrocnemius; SOL, soleus; Whole-TS, whole triceps surae.

FIGURE 4

The summary in percentage change based on the mean changes for each muscle and the whole triceps surae. ***p < 0.001, **p < 0.01 and *p < 0.05 difference between times (pre vs. post). ##p < 0.01 and #p < 0.05 difference between conditions (legs). LG, lateral gastrocnemius; MG, medial gastrocnemius; SOL, soleus; Whole-TS, whole triceps surae.