PURPOSE The function of the brachioradialis muscle is controversial. The objective of this study was to determine primary and secondary functions of the brachioradialis under various loading tasks as measured by EMG. METHODS Ten healthy individuals (9 men, 1 woman; average age, 34 years +/- 10; average height, 175 cm +/- 7; average weight, 76 kg +/- 13) performed elbow flexion with the forear...

Current trends in industry are leaning towards specialized production systems and sedentary computer work tasks that are associated with low and less varying mechanical exposures. It has been suggested that physical variation is an effective intervention to reduce local fatigue and potentially musculoskeletal disorders. However, little is known in how the differences between physical variation ...

Recently it was demonstrated that postactivation potentiation (PAP), which refers to the enhancement of the muscle twitch torque as a result of a prior conditioning contraction, increased the maximal rate of torque development of tetanic and voluntary isometric contractions (3). In this study, we investigated the effects of PAP and its decay over time on the load-velocity relation. To that purp...

A principal cause of subacromial impingement (SAI) is failure of the rotator cuff to center the humeral head in the glenoid during shoulder motion, counteracting the effect of the deltoid. As rehabilitation of the rotator cuff endeavors to restore balance between these muscle groups, the purpose of this companion study was to evaluate, in the symptomatic shoulders of patients with SAI, (1) the ...

In 11 healthy volunteers, we evaluated, in a double-blind crossover study, whether the vasodilation that follows isometric contraction is mediated by prostaglandins (PGs) and/or is O2 dependent. Subjects performed isometric handgrip for 2 min at 60% maximal voluntary contraction (MVC), after pretreatment with placebo or aspirin (600 mg orally), when breathing air or 40% O2. Forearm blood flow w...

QUESTION Can real-time visual feedback facilitate the activity of serratus anterior in individuals with scapular winging during shoulder flexion? DESIGN Comparative, repeated-measures experimental study. PARTICIPANTS Nineteen subjects with scapular winging. INTERVENTION Participants performed isometric shoulder flexion at 60° and 90° with and without real-time visual feedback using a vide...

The purpose of this study was to examine the effect of exercise-induced damage of the elbow flexor muscles on steady motor performance during isometric, shortening, and lengthening contractions. Ten healthy individuals (age 22+/-4 yr) performed four tasks with the elbow flexor muscles: a maximum voluntary contraction, a one repetition maximum (1 RM), an isometric task at three joint angles (sho...