Reliability of Pressure Pain Threshold Measurements of Upper and Lower Limb Muscles of Young Swimmers: An Observational Study

ABSTRACT Background and Purpose Objective measures should be combined with subjective assessments to monitor pain and discomfort, particularly in sports with a high prevalence of atraumatic injuries. Therefore, this study aimed to determine the reliability of pressure pain threshold (PPT) measurements in competitive swimmers and to explore the influence of intrinsic and extrinsic factors on PPT. Methods Forty‐seven swimmers were included in the study. PPT was measured bilaterally in 10 muscles of the upper and lower limbs and trunk using a hand‐held algometer. Two trained physiotherapists performed four consecutive evaluations on the same day, with a 5‐min interval between repeated measures, in randomized order to minimize carryover effects. Intrinsic variables included age, body mass index, shoulder pain, injury history, and years of practice. Extrinsic variables included swimming style, swimming distance, competitive level, training frequency, and training duration. Reliability was assessed using intraclass correlation coefficients, standard error of measurement, minimal detectable change, and coefficient of variation. The influence of intrinsic and extrinsic factors on PPT was explored using multivariate analysis of variance. Results Reliability varied from good to excellent across all muscles, with ICC values between 0.75 and 0.95. Descriptive data indicated that swimmers competing at the national level had higher PPT values compared with regional/state athletes, and butterfly specialists showed slightly higher PPTs. Across all participants, lower limb muscles consistently exhibited higher PPT values than upper limb muscles (e.g., rectus femoris mean 4.2 kg/cm 2 vs. biceps brachii mean 2.8 kg/cm 2 ). Conclusions Reliability was high across all muscles, and PPT differences observed appear to reflect training level, stroke specialization, and muscle group characteristics rather than intrinsic or injury‐related factors. Furthermore, applications up to 5 kgf are safe and well tolerated in the lower limb, which differs from the usual threshold of 2.55 kgf commonly used in the upper limb.