22 Since local muscle fatigue can be influenced by either reduced blood flow providing less needed metabolic substrates and oxygen, or by reduced flow allowing for greater buildup of metabolic wastes, a scenario where dim light or dark exposure led to reduced blood flow would be an easy and logical explanation for reduced performance. Unfortunately, current data are insufficient to strongly support such a supposition. In summary, this study reaffirms the findings that light intensity can have a deleterious effect upon muscle
endurance. selleck chemicals The mechanisms behind this negative influence cannot be clearly ascertained, and it is possible that multiple mechanisms may be involved. The lack of a clear mechanism is not surprising given that previous studies lack consistency in light intensity, exposure time and melatonin supplementation. The only thing that is clear is that successful athletic or work performance is dependent upon factors besides training state, fuel availability, and climatic conditions. Since muscle endurance is important in various situations such as athletic competition, shift work production, and military operations, it is recommended that practitioners carefully consider such simple things as the location and
light conditions of the places where performers wait find more or ready themselves pre-performance. “
“Physical examination of the dominant (throwing) shoulder of baseball players consistently demonstrates glenohumeral internal and external rotation range of motion (ROM) adaptations when compared Florfenicol to the non-dominant (non-throwing) limb.1, 2, 3, 4, 5, 6, 7 and 8 A typical baseball player presents with greater humeral external rotation (external rotation gain) and less internal rotation on the dominant limb (glenohumeral internal rotation deficit (GIRD))2, 3, 6, 9, 10 and 11 compared to their non-dominant limb. GIRD is calculated as the difference in the maximum humeral internal rotation angle between the dominant (throwing)
and nondominant (non-throwing) limbs.12 A deficit of 10°–17° of internal rotation is common in the dominant arm of throwing athletes who have not suffered a shoulder injury.2, 6 and 13 Baseball players also present with significantly increased external rotation ROM when comparing the dominant shoulder to the non-dominant shoulder.1, 2 and 14 The external rotation gain tends to range between 8° and 12° and is offset with a corresponding decrease in internal rotation.1 During the cocking phase of pitching and throwing, the high level of loading on the shoulder passive restraints may cause gradual stretching of the capsular collagen leading to an increase in external rotation ROM.15, 16 and 17 Increased external rotation ROM coupled with high joint forces can exceed the physiological limits of the shoulder joint, compromising joint stability.