The aim of the present study is to: (1) induce delayed onset muscle soreness (DOMS) in the neck and shoulder muscles; (2) compare the pressure pain sensitivity of muscle belly with that of musculotendinous tissue after DOMS; (3) examine the gender differences in the development of DOMS. An eccentric shoulder exercise was developed to induce DOMS on neck/shoulder muscles using a specially designed dynamometer. Eccentric shoulder contraction consisted of 5 bouts, each bout lasted 3min, with 3min rest period between each bout. The right shoulder was elevating against a downward pressure force of 110% maximal voluntary contraction force exerted by the dynamometer. Pressure pain thresholds (PPT) of 11 sites (seven sites measured were muscle belly and four sites were myotendinous area) on neck/shoulder region were measured before, immediately after, 24 and 48h after exercise. Pain intensity, pain area and index of McGill pain questionnaire were assessed and all were increased after exercise. DOMS was induced in the shoulder muscles. PPT was significantly decreased and reached lowest values at 24h. The muscle belly sites are more sensitive to pain than the musculotendinous sites. No gender differences were found in any of the parameters used to assess the development of DOMS. DOMS did not distribute evenly in the neck/shoulder region. Soreness after exercise in the neck and shoulder seems not to be among the conditions that produce predominant musculoskeletal pain in females.

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The study aimed to assess the effects of compression trigger point therapy on the stiffness of the trapezius muscle in professional basketball players (Part A), and the reliability of the MyotonPRO device in clinical evaluation of athletes (Part B). Twelve professional basketball players participated in Part A of the study (mean age: 19.8 ± 2.4 years, body height 197 ± 8.2 cm, body mass: 91.8 ± 11.8 kg), with unilateral neck or shoulder pain at the dominant side. Part B tested twelve right-handed male athletes (mean ± SD; age: 20.4 ± 1.2 years; body height: 178.6 ± 7.7 cm; body mass: 73.2 ± 12.6 kg). Stiffness measurements were obtained directly before and after a single session trigger point compression therapy. Measurements were performed bilaterally over 5 points covering the trapezius muscle. The effects were evaluated using a full-factorial repeated measure ANOVA and the Bonferroni post-hoc test for equal variance. A p-value < .05 was considered significant. The RM ANOVA revealed a significant decrease in muscle stiffness for the upper trapezius muscle. Specifically, muscle stiffness decreased from 243.7 ± 30.5 to 215.0 ± 48.5 N/m (11.8%), (p = .008) (Part A). The test-retest relative reliability of trapezius muscle stiffness was found to be high (ICC from 0.821 to 0.913 for measurement points). The average SEM was 23.59 N/m and the MDC 65.34 N/m, respectively (Part B). The present study showed that a single session of compression trigger point therapy can be used to significantly decrease the stiffness of the upper trapezius among professional basketball players.

No abstract

In this study, we tested the hypotheses that unaccustomed eccentric exercise (ECC) would reduce the elastic modulus and dynamic stiffness of the upper trapezius muscle and that these changes would correlate with increases in muscle thickness, reflecting muscle edema. Shear wave elastography was used to measure elastic modulus, dynamic stiffness was assessed using myotonometry, and muscle thickness was measured using ultrasonography. All measurements were performed at four locations over the upper trapezius before and 24 h after a single bout of ECC. Fourteen healthy participants (11 males and 3 females; 23.2 ± 3.0 years; height 175.1 ± 10.4 cm; body mass 73.8 ± 11.3 kg) took part in the study. Overall, ECC resulted in decreased elastic modulus (from 45.8 ± 1.6 to 39.4 ± 1.2 kPa, p < 0.01) and dynamic muscle stiffness (from 369.0 ± 7.3 to 302.6 ± 6.0 N/m, p < 0.01). Additionally, ECC resulted in increased muscle thickness (from 6.9 ± 0.4 to 7.3 ± 0.4 mm, p < 0.01). Spatial changes (across the four locations) were found for elastic modulus, stiffness and thickness. No significant correlations were found between changes in measures of muscle stiffness, or between changes in stiffness and changes in thickness. In conclusion, the present pilot study showed that ECC altered biomechanical muscle properties, reflected by decreased elastic modulus and dynamic muscle stiffness 24 h after ECC.