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Validity of diagnostic ultrasound as a measure of delayed onset muscle soreness.

STUDY DESIGN
Repeated measures were taken to evaluate delayed onset muscle soreness (DOMS) following eccentric bicep contractions of the nondominant arm at 140% of 1 repetition maximum (RM) while the dominant arm served as control.


OBJECTIVES
To explore the usefulness of a noninvasive method to assess delayed onset muscle soreness.


BACKGROUND
Although many methods have been proposed to assess DOMS, most are somewhat subjective or require a blood sample. This study compared the assessment of DOMS following eccentric exercise using common assessment techniques with diagnostic ultrasound (US).


METHODS AND MEASURES
Forty nonimpaired women (18-40 years) used a Cybex isotonic biceps curl machine to eccentrically lower, using their nondominant arm, 140% of their dominant arm 1 RM to induce muscle soreness. Four assessment methods, (1) goniometry assessing spontaneous muscle shortening (SMS); (2) subjective muscle soreness ratings (MSRs); (3) serum creatine kinase (CK); and (4) diagnostic US scans of muscle cross-sectional area (CSA), were conducted at 5 different assessment times: (1) pre-eccentric exercise; (2) postexercise; (3) 24 hours postexercise; (4) 48 hours postexercise; and (5) 72 hours postexercise.


RESULTS
Significant differences existed across assessment times for 3 of the 4 assessment techniques, CK, SMS, and MSR.


CONCLUSIONS
Previously published methodologies used to assess DOMS (CK, SMS, and MSR) were able to provide consistent and expected results relative to the onset and progression of soreness with a high degree of relatedness (r = 0.48-0.84). However, it appeared that the ability to assess muscle soreness by diagnostic US, as evidenced by intramuscular swelling, was limited. Thus, the technique was not sensitive enough to detect any statistically significant changes in muscle CSA.