Jared R. Fletcher (author); Brian R. MacIntosh (author)
Date issued
2018; 2018
Description
During prolonged running, the magnitude of Achilles tendon (AT) length change may increase, resulting in increased tendon strain energy return with each step. AT elongation might also affect the magnitude of triceps surae (TS) muscle shortening and shortening velocity, requiring greater activation and increased muscle energy cost. Therefore, we aimed to quantify the tendon strain energy return and muscle energy cost necessary to allow energy storage to occur prior to and following prolonged running. 14 trained male (n = 10) and female (n = 4) distance runners (24 +/- 4 years, 1.72 +/- 0.09 m, 61 +/- 10 kg, (V) over barO(2)max 64.6 +/- 5.8 ml.kg(-1).min(-1)) ran 90 minutes (RUN) at...
Sasa Cigoja (author); Jared R. Fletcher (author); Michael Esposito (author); Darren J. Stefanyshyn (author); Benno M. Nigg (author)
Date issued
2021-01-01; 2021-01-01
Description
In recent years, increasing the midsole bending stifness (MBS) of running shoes by embedding carbon fbre plates in the midsole resulted in many world records set during long-distance running competitions. Although several theories were introduced to unravel the mechanisms behind these performance benefts, no defnitive explanation was provided so far. This study aimed to investigate how the function of the gastrocnemius medialis (GM) muscle and Achilles tendon is altered when running in shoes with increased MBS. Here, we provide the frst direct evidence that the amount and velocity of GM muscle fascicle shortening is reduced when running with increased MBS. Compared to control, running in...
Jared R. Fletcher (author); University of Calgary Faculty of Graduate Studies (Degree granting institution)
Date issued
2014-12; 2014-12
Description
Recently published reports suggest the role of the muscles and tendons of the lower limbs are an important factor in determining the energy cost of running (Erun). Specifically, there exists a link between the mechanical properties of the Achilles tendon (AT) and Erun but the impact of the muscle’s energy cost is not considered. To date, very little is known regarding the interaction between AT stiffness, muscle energetics and Erun. Further, little is known about the AT stiffnessenergetics relationship in female runners. Therefore, the overall goal of this thesis was to explore the relationship between AT stiffness and muscle energetics in male and female distance runners. The first study...
