CHANGE IN SKELETAL MUSCLE STIFFNESS AFTER RUNNING COMPETITION IS DEPENDENT ON BOTH RUNNING DISTANCE AND RECOVERY TIME

Open Access
Author:
Newman, Cassidy
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Daniel Cortes, Thesis Supervisor
  • Sean Brennan, Honors Advisor
Keywords:
  • mechanical properties
  • skeletal
  • muscle
  • running
  • changes
  • stiffness
  • time
  • distance
  • shear wave elastography
  • ultrasound
Abstract:
Quantifying muscle adaptation and remodeling in runners is important to design proper training strategies and avoid injury. The goal of this study is to understand how the mechanical properties of skeletal muscles adapt to running competitions of various distances. Our objective is to use shear wave elastography (SWE) to monitor skeletal muscle stiffness changes of 22 subjects after a short distance (3-5 miles), medium distance (10-14 miles) or long distance (26+ miles) race. Quantitative shear wave velocity and shear modulus measurements were taken of the rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), soleus, lateral gastrocnemius (LG), medial gastrocnemius (MG), biceps femoris (BF), and semitendinosus (ST) muscles at three time points: 24 hours before competition, 24 hours after competition, and one week after competition. Time was found to have a significant effect on the soleus (p = 0.0242), RF (p = 0.0490) and ST (p = 0.0444) muscles and distance was found to have a significant effect on the BF (p = 0.0178), RF (p = 0.0463) and ST (p = 0.0124) muscles. Sixty-seven percent of muscles exhibited a decreasing stiffness trend from before competition to immediately after competition, proving that recovery time does in fact have a significant effect on the mechanical properties of muscles. The results also suggest that running distance has an effect on muscle mechanical properties. The specific effect of time and distance, however, seems to vary between individual muscles or subjects. This discrepancy is most likely due to the many factors that affect the forces applied to individual muscles such as running form, topography of training courses and intensity of training.