Fig. 3.

In vivo wave speed measurements. a Shear wave tensiometers secured over the patellar and Achilles tendons. b The tensiometers consisted of a piezo-actuated tapper and two miniature accelerometers spaced a fixed distance apart. c Representative recording of patellar tendon transverse accelerations demonstrate that the travel time (Δt) between accelerometers is shorter in the high load condition, reflecting faster wave propagation. d Linear relationships between joint torque and squared wave speed (binned means ± 1 s.d. for a representative subject) were observed in both tendons across a range of loading rates