Lower extremity work along with triceps surae structure and activation is altered with jumping after Achilles tendon repair

Abstract

Achilles tendon rupture leads to long term plantar flexor deficits. The purpose of this study was to describe changes in jumping biomechanics along with triceps surae structure and activation in individuals after Achilles repair. Eleven individuals 1–3 years following Achilles repair and 10 healthy controls were included. Kinetics and kinematics, analyzed using a constituent lower extremity work (CLEW) approach, and muscle activity using surface electromyography (EMG) were collected during a unilateral hopping task. Triceps surae myotendinous structure was assessed using ultrasound imaging. There were no differences in jump height, absolute limb work, or cost of transport between groups. During takeoff, the knee did more (p < 0.001) and ankle did less concentric work (p < 0.001), and lateral gastrocnemius rate of rise was higher (p = 0.02) on the ruptured side. During landing, the knee did more eccentric work (p = 0.033) and lateral gastrocnemius (p = 0.003) and soleus (p = 0.02) activation amplitude prior to landing was higher on the ruptured side. Individuals after Achilles tendon repair shift work toward the knee and alter muscle recruitment. Differences in lateral gastrocnemius activity may indicate that it is well‐situated to generate power during takeoff and assist in landing with the soleus. The lack of change in muscle activity and decreased cross sectional area of the medial gastrocnemius may suggest that this muscle atrophies and does not accommodate to the hopping task. Clinical Significance: Proximal lower extremity strengthening along with emphasizing medial gastrocnemius and soleus activation during the recovery of patients with Achilles tendon repair may be rehabilitative targets for improved jumping performance. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

Medial gastrocnemius muscle remodeling correlates with reduced plantarflexor kinetics 14 weeks following Achilles tendon rupture

“…Single-leg heel raise height positively correlates with resting gastrocnemius length (1) and active shortening (22). Patients compensate for reduced plantarflexor function during gait and jumping by increasing the work done by the proximal knee joint (26,30). These reports suggest that Achilles tendon ruptures alter skeletal muscle function, which may explain long-term functional deficits.…”

Whole body muscle activity during weightlifting exercise evaluated by positron emission tomography

“…In the triceps surae, the soleus muscle showed signi cant muscle activity compared to the gastrocnemius muscle. A previous study evaluating muscle activity in the gastrocnemius and soleus muscles during the two-foot hopping task reported that there was muscle activity only in the soleus muscle [24,25]. The gastrocnemius muscle is a biarticular muscle, and it is possible that muscle activity is inhibited by knee extension.…”

Gastrocnemius muscle remodeling explains functional deficits three months following Achilles tendon rupture

“…10 Following Achilles tendon ruptures, patients have compromised plantarflexor function and compensate by increasing the work done by the proximal knee joint. 11 Gastrocnemius muscle remodeling occurs following Achilles tendon ruptures, 12,13 which appears to be in response to a sudden loss of muscle-tendon tension. Acute Achilles tendon ruptures have been shown to elicit shorter and more pennate gastrocnemius muscle fascicles at rest.…”