Overhead Shoulder Position Versus Scapular Retraction Position to Normalize the Electromyographic Signal of the Lower Trapezius Muscle.

This study aimed to compare electromyographic response of the lower trapezius muscle during maximal voluntary isometric contractions under two conditions: overhead shoulder position versus scapular position, rating the pain after each condition. Twenty-six participants with shoulder pain (SP; n = 15; Shoulder Pain and Disability Index-Pain = 34 [range 6-66]) and without shoulder pain (nSP; n = 11; Shoulder Pain and Disability Index-Pain = 0 [range 0-14]) performed maximal voluntary isometric contractions in those 2 conditions while the lower trapezius was monitored using surface electromyography. Pain was rated using the visual analog scale. The nSP group experienced no pain, whereas the SP group reported pain in both conditions with higher pain during the overhead movement. No differences were observed for muscle excitation between conditions, but higher levels were observed for the nSP group compared with the SP group. The overhead condition was more painful for the SP group (visual analog scale: SP = 4 vs nSP = 1.09, P = .036). Scapular position showed the same levels of LT excitation than overhead position. The scapular position is preferable, compared with overhead positioning, to normalize the lower trapezius instead of overhead positioning.

Effects of 4-Week Diacutaneous Fibrolysis on Myalgia, Mouth Opening, and Level of Functional Severity in Women With Temporomandibular Disorders: A Randomized Controlled Trial.

OBJECTIVE: The purpose of this study was to assess the effects of 4-week protocol of diacutaneous fibrolysis (DF) compared with simulated DF (sham-DF) on myalgia and mouth opening. METHODS: In a sham randomized controlled trial, 34 women with temporomandibular disorders and myofascial pain were randomly divided as intervention group (IG) and sham-DF group (SG). The IG received 4 weeks of real DF, and the SG received sham. Pain was assessed through the visual analog scale and pressure pain thresholds (PPTs) on the temporomandibular joint (TMJ), and over the temporal and masseter muscles. The Mandibular Function Impairment Questionnaire was used to classify the participants regarding to the severity of the functional limitation related to TMD. RESULTS: Pain scores decreased for both groups, but the IG showed lower values at week 4, with between-group differences. Bilateral temporal PPT showed higher values at week 4, with between-group differences. The SG had lower PPTs but the IG had higher PPTs, both compared to baseline results. The time-by-group interaction and the frequency of participants above 40 mm of mouth opening showed a significant difference for the IG over time with higher results at the 4-week assessment compared to its own baseline. Both groups showed lower MFIQ scores from baseline to 4-week assessment. There was a lower frequency of a moderate level of severity for the IG. No differences were observed for TMJ or for the masseter muscles PPT. CONCLUSION: Improvements were observed for visual analog scale scores and PPTs on temporal muscles. There was a group-by-time interaction in the IG, suggesting a possible potential use of DF for mouth opening.

Interquartile differences in biomechanical parameters in CrossFit® athletes during deep squats with submaximal load until fatigue.

BACKGROUND: CrossFit® exercises are demanding and require high power outputs sustained over time, therefore the daily workouts (WOD) could provoke considerable fatigue and lead to injury in a subsequent exercise session. To improve performance and prevent injury, the effect of pacing strategies has to be studied, by observing how fatigue modifies movement biodynamics until muscle failure. Thus, the present study aimed to analyze the interquartile differences in biomechanical parameters in CrossFit® athletes during deep squats with submaximal load until fatigue. METHODS: This is a comparative and descriptive applied research study using electromyographic analysis. Twenty CrossFit® competition athletes participated in this study (age 27±6 years; training experience 14.4±7.7 months; weight 80±11 kg; height 175±7 cm; BMI 26±3 kg/m2). RESULTS: The mean time until fatigue was 14±8 minutes. Pairwise comparisons confirmed fatigue by using the lactate results (pre=1.80 mg/dL, post=12.60 mg/dL; P=0.0001). Significant differences were noted among quartiles (Pillai's trace F=3.99; P=0.001) on the composite variable. CONCLUSIONS: The results supported the hypothesis of self-regulation and showed higher velocity associated with higher maximal power. Concentric muscular recruitment was associated to the detriment of the eccentric phase during progressive fatigue. Coaches and athletes can apply the results of the present study when establishing WOD strategies during training and competition.