Calf muscle architecture and function in ultra runners and low physical activity individuals: A comparative review

Abstract

Introduction: There is a high incidence of calf injuries in ultradistance runners. Due to the low load, high volume nature of ultradistance running, the stimulation for adaptation in the gastrocnemius from running alone, may not be sufficient to stimulate adaptation. The purpose of this study was to assess the adaption in the architectural and functional components of the calf in ultradistance runners. Methods: Thirty participants (16 ultradistance runners, 14 low physical activities)were recruited for this study. Ultrasound assessment of the gastrocnemius muscle architecture, including fascicle length, thickness, pennation angle, volume, and physiological cross-sectional area was performed. Functional tests assessing calf flexibility and calf muscle-tendon unit endurance were performed. Results: No significant differences were observed in medial gastrocnemius thickness, fascicle length, or pennation angle between groups. Gastrocnemius PCSA and volume were significantly increased in runners compared to low physical activity participants (P = 0.01 and P = 0.02, respectively). Average calf endurance was significantly increased in runners (P = 0.03). Conclusions:Ultradistance running training appears to stimulate relatively few changes in the medial gastrocnemius. It is possible that an absence of adaptation in the architecture of the medial gastrocnemius in response to endurance training might contribute to the high incidence of calf injuries among ultradistance runners. K E Y W O R D Sarchitecture, gastrocnemius, running, ultradistance, ultrasound

Investigation of the Impact of Below-Knee Compression Garments on Markers of Exercise-Induced Muscle Damage and Performance in Endurance Runners: A Prospective Randomized Controlled Trial

“…Scans were performed at the midpoint between the proximal and distal musculotendinous junctions. 13 Pennation angle was calculated as the angle between the muscle fascicles and the deep aponeurosis while thickness was calculated as the distance between the superficial and deep aponeuroses with measurements taken perpendicularly at the middle of each image. Each measurement was performed twice and average values recorded.…”

“…9 Pennation angle and muscle thickness of the medial gastrocnemius was determined using a Siemens ACUSONX150 diagnostic ultrasound machine using previously reported settings. 13 The right legs of participants were tested in prone position with the ankle maintained at 90° plantarflexion with a firm footplate. Participants were instructed to relax the muscle during imaging.…”