FLEXIBILITY AND ITS EFFECTS ON SPORTS INJURY AND PERFORMANCE

Flexibility measures can be static [end of ROM (range of motion)], dyn amic-passive (stiffness/compliance) or dynamic-active (muscle contract ed, stiffness/compliance). Dynamic measures of flexibility are less de pendent on patient discomfort and are more objective. Acute and chroni c changes in flexibility are likely to occur with stretching exercises , but it is difficult tb distinguish between changes in stretch tolera nce as opposed to changes in muscle stiffness. How flexibility is meas ured impacts these findings. There-is no scientifically based prescrip tion for flexibility training and no conclusive statements can be made about the relationship of flexibility to athletic injury. The literat ure reports opposing findings from different samples, frequently does not distinguish between strain, sprain and overuse injury, and rarely uses the proper denominator of exposure. There is basic scientific evi dence to suggest that active warm-up may be protective against muscle strain injury but clinical research is equivocal on this point. Typica lly, specific flexibility patterns are associated with specific sports and even positions within sports. The relationship of flexibility to athletic performance is likely to be sport-dependent. Decreased flexib ility has been associated with increased in-line running and walking e conomy. Increased stiffness may be associated with increased isometric and concentric force generation, and muscle energy storage may be bes t manifested by closely matching muscle stiffness to the frequency of movement in stretch-shorten type contractions.