Effects of different stretch durations on the strength of the proximal and distal group of muscles - a randomized trial.

BACKGROUND: Different researchers have studied the effects of different types of stretching on different muscle groups. Since distal muscles are fully activated and proximal muscles are sub-optimally activated; thus, we might see different responses to stretching in the proximal and distal groups of muscles depending on their muscle activation. Therefore, this study aimed to compare the acute effects of 2, 4, and 8 minutes of intermittent static stretching (SS) on the isometric maximum voluntary contraction force (MVCF) of proximal (Hamstring) and distal (Calf) groups of muscles. METHODS: Two groups pretest-posttest experimental design was used. A total of thirty participants were randomly assigned into two groups, and twenty-eight completed the intervention. In both groups, participants participated in three experimental trials (SS2, SS4, and SS8) on 3 days. 2-minute intermittent stretching (SS2) was performed on day-I, 4-minute (SS4) on day II, and 8-minute (SS8) on day III. Isometric MVCF was measured at pre-intervention, 0-, 10-, and 20-minute post-intervention periods in both groups. RESULTS: In the proximal group: SS2, SS4, and SS8 did not affect isometric MVCF at the 0-, 10-, and 20-minute post-intervention periods (P > .05). In distal group: SS2 did not affect isometric MVCF at 0- and 10-minute post-intervention periods (P > .05), however at 20-minute, MVCF increased by 11.06% (P < .05). SS4 and SS8 also did not alter isometric MVCF in the Calf at 0-, 10-, and 20-minute post-intervention periods (P > .05). No significant differences were observed between the proximal and distal groups (P > .05). CONCLUSION: 2-, 4-, and 8-minute intermittent SS did not affect the isometric strength in both muscle groups. In addition, proximal and distal groups of muscles responded similarly to three different duration intermittent SS.

Effects of Deep Cervical Flexor Training on Forward Head Posture, Neck Pain, and Functional Status in Adolescents Using Computer Regularly.

In contemporary societies, computer use by children is a necessity and thus highly prevalent. Using computers for long hours is related to a higher risk of computer-related muscular disorders like forward head posture (FHP) and neck pain (NP). Deep cervical flexor (DCF) muscles are important head-on-neck posture stabilizers; thus, their training may lead to an improvement in FHP and NP. The aim of this study was to determine if 4 weeks of DCF training is effective in alleviating NP, improving FHP, and functional status in adolescent children using computers regularly, a pretest-posttest experimental group design was used. Subjects were randomly assigned into the experimental group (receiving DCF training and postural education) and the control group (receiving postural education only). 30 subjects with a mean age of 15.7 ± 1.725 years with NP and FHP using computers regularly participated in the study. Dependent variables were measured on day 1 (at baseline) and after 4 weeks of training. Photographic analysis was used for measuring FHP, visual analog scale for NP intensity, and neck disability index for functional status. Data analysis showed that in both groups, no significant improvement occurred in FHP. In both groups, there was a significant improvement in functional status and NP. There was no significant difference between both groups for FHP and NP. There was a significant improvement in functional status in the experimental group in comparison to the control group. Four weeks of DCF training does not cause a significant improvement in FHP in 13 to 18 years old adolescent children using computers regularly.