Immediate changes in chest mobility and trunk muscle activity during pelvic tilt following different trunk muscle exercises.

BACKGROUND: Given the characteristics of the superficial trunk muscles that cross the chest and pelvis, their excessive contraction might limit chest mobility. OBJECTIVE: To examine the immediate effects of two types of trunk muscle exercises on chest mobility and trunk muscle activities. METHODS: Fourteen healthy men (age: 21.1 ± 1.0 years, height: 172.7 ± 5.6 cm, weight: 61.0 ± 7.1 kg, body mass index: 20.4 ± 1.7 kg/m2; mean ± SD) randomly performed trunk side flexion and draw-in exercises using a cross-over design. The chest kinematic data and trunk muscle activities were measured before and after each intervention during the following tasks: maximum inspiration/expiration and maximum pelvic anterior/posterior tilt while standing. Two-way repeated measures analysis of variance was used for statistical analysis (P< 0.05). RESULTS: After the side flexion, upper and lower chest mobility significantly decreased, and superficial trunk muscle activity significantly increased during the maximum pelvic anterior tilt (P< 0.05). Additionally, after the draw-in, upper chest mobility significantly increased during the maximum pelvic anterior tilt (P< 0.05). CONCLUSIONS: Increased activity of the superficial abdominal muscles might limit chest mobility during maximum pelvic anterior tilt. Conversely, the facilitation of deep trunk muscles might increase upper chest mobility during the maximum pelvic anterior tilt.

Iliopsoas Disorder in Athletes with Groin Pain: Prevalence in 638 Consecutive Patients Assessed with MRI and Clinical Results in 134 Patients with Signal Intensity Changes in the Iliopsoas.

BACKGROUND: Although iliopsoas disorder is one of the most frequent causes of groin pain in athletes, little is known about its prevalence and clinical impact. METHODS: We retrospectively reviewed the cases of 638 consecutive athletes who had groin pain. Each athlete was assessed with magnetic resonance imaging (MRI). First, we identified the prevalence of changes in signal intensity in the iliopsoas. Then we classified the changes in signal intensity in the iliopsoas, as visualized on short tau inversion recovery MRI, into 2 types: the muscle-strain type (characterized by a massive high-signal area in the muscle belly, with a clear border) and the peritendinitis type (characterized by a long and thin high-signal area extending proximally along the iliopsoas tendon from the lesser trochanter, without a clear border). Finally, we compared the time to return to play for the athletes who had these signal intensity changes. RESULTS: Changes in signal intensity in the iliopsoas were detected in 134 (21.0%) of the 638 athletes. According to our MRI classification, 66 athletes had peritendinitis changes and 68 had muscle-strain changes. The time from the onset of groin pain to return to play was significantly shorter for the patients with muscle-strain changes on MRI than for those with peritendinitis changes (8.6 ± 8.3 versus 20.1 ± 13.9 weeks, respectively; p < 0.0001). CONCLUSIONS: Changes in MRI signal intensity in the iliopsoas were observed in 21.0% of 638 athletes who had groin pain. Distinguishing between muscle-strain changes and peritendinitis changes could help to determine the time to return to play.