Effect of a period of cervical flexion on upper extremity muscle strength

Abstract

Background: Technology is prevalent in almost every aspect of life, from handheld phones to computers. Increases in cervical flexion can cause a strain on the neck and muscles of the upper extremity.
 Objective: To examine the effect of 30 minutes of cervical flexion at 45 degrees. It was hypothesized that muscle strength will decrease after flexion, and there would be no significant differences between dominant and nondominant arms or genders.
 Study design: Twenty-four participants (12 male, 12 female) (n = 24; height = 173.1 + 9.3 cm; weight = 73.33 + 22.58kg) were measured before and after cervical flexion using a MicroFET2 Hand Held Digital Muscle Tester to test the middle deltoid, biceps brachii, and triceps brachii of each arm.
 Results: Compared to pre-measures significant differences were found in both middle deltoids and both biceps brachii, but not in either triceps brachii (p < 0.05). Overall no limited significant differences were found between genders of muscles of either arm. Significant differences (p < 0.05) were found in the dominant biceps brachii, non-dominant biceps brachii, dominant triceps brachii, dominant deltoid, and non-dominant deltoid.
 Conclusion: These results suggest that a normal daily degree of cervical flexion will decrease some upper extremity strength over the course of 30 minutes.