Acute inflammation response to stretching: a randomised trial

Abstract

Background: The aim of the study was to examine the effects of an intense stretch on selected serum-based muscle inflammation biomarkers. Methods: A randomised within-subject crossover trial was conducted with 12 healthy recreationally active males (age: 29±4.33yrs, mass: 79.3±8.78kg, height: 1.76±0.06m) participating in both an intense stretching and control intervention. During the stretch intervention the hamstrings, gluteals and quadriceps were exposed to an intense stretch by the same therapist, in order to standardise the stretch intensity for all participants. The stretch was maintained at a level rated as discomfort and/or mild pain with use of a numerical rating scale (NRS). Each muscle group was stretched for 3 x 60 seconds for both sides of the body equating to a total of 18 minutes. During the control intervention, participants rested for an equivalent amount of time. A 5ml blood sample was collected pre-, immediately post, and at 24h post for both conditions to assess the levels of interleukin (IL)-6, interleukin (IL)-1β, tumour necrosis factor (TNF)-α, and high sensitivity C-reactive protein (hsCRP). Participants provided information about their level of muscle soreness 24, 48, and 72h post treatment, using a numeric rating scale. Results: hsCRP increased significantly at 24h compared to control and immediate post stretch intervention, for time (p=0.005), and time x condition (p=0.006). No significance was observed for IL-6, IL-1β or TNF-α (p>0.05). Conclusion: It is observed that intense stretching may lead to an acute inflammatory response supported by the significant increase in hsCRP.