Participant and Researcher Perceptions of Stretching Intensity and Muscle Tension in A Hamstrings and Shoulder Stretch in Healthy Young Adults.

There were no significant differences between participant and researcher measurements at initial or maximum stretch endpoints, but correlation and agreement between perceptions were variable.

• 18 young adult participants were assessed during supine hip flexion and shoulder extension passive stretches
• Joint angles at initial stretch sensation and maximum tolerable stretch were recorded by a secondary researcher while the blinded primary researcher recorded initial and maximum tension perceptions
• Correlation and agreement between participant and researcher perceptions were described as 'variable' despite non-significant differences in mean values
• Overall reliability of participant and researcher perceptions was described as 'excellent' for both hip flexion and shoulder stretches

There was a large magnitude but non-significant difference between researcher and participant maximum hip flexion measurements, with researcher measurements higher than participants'.

• Overall large magnitude effect (eta2 = 0.794) for the difference between researcher maximum and participant maximum hip flexion
• The difference was non-significant (p = 0.06)
• Researcher maximum hip flexion measurements: 108.39° ± 17.22°
• Participant maximum hip flexion measurements: 98.6° ± 20.08°
• The mean difference was more apparent with greater divergence observed in less trained individuals and those with less stretching experience

Greater hip flexion ROM was observed for women, athletes, and participants with stretching experience, as well as when stretching to maximum versus initial point of discomfort.

• Sex, trained state, and stretching experience were all associated with greater hip flexion ROM
• Stretching to maximum tolerable stretch produced greater ROM than stretching to the initial point of discomfort
• These group differences were observed specifically for hip flexion and not shoulder extension
• Training status and stretching experience were identified as important moderating variables

Shoulder extension ROM did not reveal any group differences based on sex, trained state, or stretching experience.

• Unlike hip flexion, shoulder extension showed no significant differences between groups
• No differences were found for sex, trained state, or stretch experience in shoulder extension ROM
• Both supine hip flexion and shoulder extension protocols were assessed in the same 18 participants

Lower correlations between participant and researcher perceptions were found for sedentary and stretching-inexperienced individuals.

• Participants with less training and stretching experience showed greater divergence between internal and external stretch perception
• The researchers noted this was most apparent at the maximum stretch endpoint
• This finding highlights the need for training status and stretching experience to be considered in stretching intensity prescription and scale development
• The study considered both training status and stretching experience as moderating variables across 18 young adult participants

Stretching research relies heavily on internal and clinical perceptions of stretching sensation for intensity prescription, yet no prior research had assessed the relationship between internal and external perceptions of stretch intensity.

• The lack of equipment required for perception-based intensity prescription is cited as a reason for its widespread use
• This study was designed to fill the gap by directly comparing participant (internal) and researcher (external) perceptions
• The blinded primary researcher was not aware of participant signals when recording their own tension perceptions
• A secondary researcher recorded joint angles when participants signaled stretch sensations