Myotendinous Thermoregulation in National Level Sprinters after a Unilateral Fatigue Acute Bout-A Descriptive Study

Abstract

In the last decade there has been a growing interest in infrared thermography in the field of sports medicine in order to elucidate the mechanisms of thermoregulation. The aim of this study was to describe bilateral variations in skin temperature of the anterior thigh and patellar tendon in healthy athletes and to provide a model of baseline tendon and muscle thermoregulation in healthy sprinters following a unilateral isokinetic fatigue protocol. Fifteen healthy national-level sprinters (eleven men and four women), with at least 3 years of athletic training experience of 10-12 h/week and competing in national-level competitions, underwent unilateral isokinetic force testing and electrostimulation in which their body temperature was measured before, during, and after the protocol using an infrared thermographic camera. ANOVA detected a significant difference in the time × side interaction for patellar temperature changes (p ≤ 0.001) and a significant difference in the time/side interaction for quadriceps temperature changes (p ≤ 0.001). The thermal challenge produces homogeneous changes evident in quadriceps areas, but not homogeneous in tendon areas. These data show that metabolic and blood flow changes may depend on the physical and mechanical properties of each tissue. Future research could be conducted to evaluate the predictive value of neuromuscular fatigue in the patellar tendon and quadriceps after exercise in order to optimize post-exercise recovery strategies.

Keywords: body temperature regulation; quadriceps muscle; tendons; thermography.

Figure 1

Patellar thermography during protocol. (A) Basal thermography and (B) final thermography.

Figure 2

Patellar skin surface temperature changes were measured by infrared thermography during the exercise protocol. B = rest; W = warm-up; 1st ELEC = first electrostimulation; ISO = isokinetic and 2nd ELEC = second electrostimulation. * = p ≤ 0.05 between ISO and 2nd ELEC on the left leg. # = p ≤ 0.05 between both sides.

Figure 3

Quadriceps skin surface temperature changes were measured by infrared thermography during the exercise protocol. B = rest; W = warm-up; 1st ELEC = first electrostimulation; ISO = isokinetic and 2nd ELEC = second electrostimulation. * = p ≤ 0.05 between W and 2nd ELEC in the left leg. ** = p ≤ 0.05 between B and 2nd ELEC in both legs. # = p ≤ 0.05 between both sides.