***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: To study the efficacy of an injury prevention program in a r and omized trial , 12 teams ( 180 players ) in a male senior soccer division were followed up for 6 months . The 12 teams were allocated at r and om to two groups of six teams , one being given a prophylactic program and the other serving as control . The program was based on previous studies of injury mechanisms . It comprised ( 1 ) correction of training , ( 2 ) provision of optimum equipment ; ( 3 ) prophylactic ankle taping ; ( 4 ) controlled rehabilitation ; ( 5 ) exclusion of players with grave knee instability ; ( 6 ) information about the impor tance of disciplined play and the increased risk of injury at training camps ; and ( 7 ) correction and supervision by doctor(s ) and physiotherapist(s ) . The injuries in the test teams were 75 % fewer than in the controls . The most common types of soccer injuries , sprains and strains to ankles and knees , were all significantly reduced . It is concluded that the pro posed prophylactic program , including close supervi sion and correction by doctors and physiotherapists , significantly reduces soccer injuries BACKGROUND AND PURPOSE The purpose s of this study were ( 1 ) to examine the effects of a passive hip extension stretching exercise program on hip extension range of motion ( ROM ) , ( 2 ) to examine the effects of a trunk flexor exercise program on trunk flexor muscle performance , and ( 3 ) to examine the effects of passive hip extension stretching or trunk flexor exercises on walking and running economy . ( " Gait economy " is defined as the steady-state oxygen consumption per unit of body weight required to walk or run at a specified velocity . ) SUBJECTS Twenty-five healthy , athletic , male college students ( mean age = 21 years , mean weight = 75 kg , mean height = 172 cm ) were r and omly assigned to one of three groups : a control group ( n = 7 ) , a hip extension stretching group ( n = 9 ) , or a trunk flexor exercise group ( n = 9 ) . METHODS Before and after 3 weeks of intervention , the following measurements were obtained : right and left hip extension ROM , trunk flexor muscle performance , and walking and running economy . A three x two-way ( groups x test sessions ) analysis of variance ( ANOVA ) for repeated measures for unequal subject numbers was performed on each of the five dependent measures , with analysis of simple main effects applied when significant interactions were found . RESULTS The ANOVA on right and left hip extension ROM revealed a significant interaction . Analyses of simple main effects showed that 3 weeks ( six sessions ) of passive hip extension stretching significantly improved right hip extension ROM ( pretest = -20.4 degrees , posttest = -8.3 degrees ) and left hip extension ROM ( pretest = -16.8 degrees , posttest = -7.0 degrees ) . There also was a significant interaction for trunk flexor muscle performance . The analysis of simple main effects revealed that 3 weeks of daily trunk flexor exercises significantly improved trunk flexor muscle performance ( pretest = 41.5 degrees , posttest = 60.4 degrees ) . The 3-week intervention program of hip extension stretching or trunk flexion exercises , however , did not produce significant changes in walking or running economy . CONCLUSION AND DISCUSSION The results suggest that ( 1 ) six treatment sessions of passive stretching were sufficient to improve hip extension ROM ; ( 2 ) 3 weeks of exercises performed daily improved trunk flexor muscle performance ; and ( 3 ) training of isolated tasks , such as hip flexibility or trunk strengthening activities , did not produce the desired outcome in the economy of walking or running . Possible reasons for the results are discussed OBJECTIVE Increased muscle flexibility from static stretching is supported by the literature , but limited research has assessed the duration of maintained flexibility gains in knee joint range of motion after same-day static hamstring stretching . The purpose of our study was to determine the duration of hamstring flexibility gains , as measured by an active knee-extension test , after cessation of an acute static stretching protocol . DESIGN AND SETTING All subjects performed 6 active warm-up knee extensions , with the last repetition serving as the baseline comparison measurement . After warm-up , the experimental group performed 4 30-second static stretches separated by 15-second rests . SUBJECTS Thirty male subjects ( age = 19.8 + /- 5.1 years , ht = 179.4 + /- 18.7 cm , wt = 78.5 + /- 26.9 kg ) with limited hamstring flexibility of the right lower extremity were r and omly assigned to control and experimental groups . MEASUREMENTS Postexercise active knee-extension measurements for both groups were recorded at 1 , 3 , 6 , 9 , 15 , and 30 minutes . RESULTS Tukey post hoc analysis indicated significant improvement of knee-extension range of motion in the experimental group that lasted 3 minutes after cessation of the static stretching protocol . Subsequent measurements after 3 minutes were not statistically different from baseline . A dependent t test revealed a significant increase in knee-extension range of motion when comparing the first to the sixth active warm-up repetition . CONCLUSIONS Our results suggest that 4 consecutive 30-second static stretches enhanced hamstring flexibility ( as determined by increased knee-extension range of motion ) , but this effect lasted only 3 minutes after cessation of the stretching protocol . Future research should examine the effect of other stretching techniques in maintaining same-day flexibility gains Two-hundred and ninety-four male and 224 female r and omly selected recreational cyclists responded to a mail question naire . Significant differences were observed between male and female cyclists ' training characteristics . Overall , 85 % of the cyclists reported one or more overuse injury , with 36 % requiring medical treatment . The most common anatomical sites for overuse injury/complaints reported by the male and female cyclists combined were the neck ( 48.8 % ) , followed by the knees ( 41.7 % ) , groin/buttocks ( 36.1 % ) , h and s ( 31.1 % ) , and back ( 30.3 % ) . For the male cyclists , effect upon back and groin/buttocks overuse injuries/complaints were miles/week , lower number of gears , and less years of cycling . For female cyclists , training characteristics which had the most significant effect upon groin/buttocks overuse injury/complaints were more non-competitive events/year and less stretching before cycling . The odds of female cyclists developing neck and shoulder overuse injury/complaints were 1.5 and 2.0 times more , respectively than their male counterparts Young female players in European h and ball have a very high injury incidence , up to 50 injuries per 1000 hours of game . More than half of these injuries happen without any external cause . The aim of the study was to investigate the effect of an intervention programme design ed to reduce the number of injuries in young female players in European h and ball , with special emphasis on injuries in the lower extremities . The programme was created using elite athlete training programmes and those design ed for rehabilitation of injured athletes with functional instability of their ankles and rupture of the anterior cruciate ligament . It included the use of an ankle disk for 10 - 15 min at all practice sessions , for one 10-month season ( August 1995-May 1996 ) . Twenty-two teams participated in the study , and were r and omly assigned to the intervention or control group . Eleven teams with 111 players were r and omised to the intervention group and 11 teams with 126 players to the control group . Data were analysed using a t-test for continuous variables , chi2- analysis and Fisher 's exact test for dichotomous variables and multivariate methods to determine odds-ratios . The results indicated that using the intervention programme decreased the numbers of both traumatic and overuse injuries significantly . The differences in injuries between the groups were 80 % during games and 71 % during practice . In addition , the players in the control group had a 5.9 times higher risk of acquiring an injury than the players in the intervention group Forty-seven male subjects were r and omly assigned to 4 different groups . Three groups of 10 subjects trained three times a week with a modified contract-relax ( CR ) method for improving muscle flexibility . Seventeen sub jects trained during the same time with a traditional ballistic stretch ( BS ) method . After 30 days ( 14 training sessions ) the latter group switched over to the CR method . The results showed that the CR method was significantly better than the BS method for improving muscle flexibility in the four different , bilateral muscle groups studied . After the initial 30 days the three groups of 10 subjects trained one , three , and five times a week , respectively , for another 30 days . The results showed that once a week was enough to maintain improved flexibility , while three and five times a week increased it further . The former BS group improved muscle flexibility between the 30th and 60th day , as expected from the results of the initial 30 days with the three CR groups , when training with the CR method three times a week To prospect ively evaluate the effect of neuromuscular training on the incidence of knee injury in female athletes , we monitored two groups of female athletes , one trained before sports participation and the other not trained , and a group of untrained male athletes throughout the high school soccer , volleyball , and basketball seasons . Weekly reports included the number of practice and competition exposures and mechanism of injury . There were 14 serious knee injuries in the 1263 athletes tracked through the study . Ten of 463 untrained female athletes sustained serious knee injuries ( 8 noncontact ) , 2 of 366 trained female athletes sustained serious knee injuries ( 0 noncontact ) , and 2 of 434 male athletes sustained serious knee injuries ( 1 noncontact ) . The knee injury incidence per 1000 athlete-exposures was 0.43 in untrained female athletes , 0.12 in trained female athletes , and 0.09 in male athletes ( P 0.02 , chi-square analysis ) . Untrained female athletes had a 3.6 times higher incidence of knee injury than trained female athletes ( P 0.05 ) and 4.8 times higher than male athletes ( P 0.03 ) . The incidence of knee injury in trained female athletes was not significantly different from that in untrained male athletes ( P 0.86 ) . The difference in the incidence of noncontact injuries between the female groups was also significant ( P 0.01 ) . This prospect i ve study demonstrated a decreased incidence of knee injury  in female athletes after a specific plyometric training program The effect of a combination of a warm-up , stretching exercises and massage on subjective scores for  delayed onset muscle soreness ( DOMS )  and objective functional and biochemical measures was studied . Fifty people , r and omly divided in a treatment and a control group , performed eccentric exercise with the forearm flexors for 30 min . The treatment group additionally performed a warm-up and underwent a stretching protocol before the eccentric exercise and massage afterwards .  Functional and biochemical measures were obtained before , and 1 , 24 , 48 , 72 and 96h after exercise . The median values at the five post-exercise time points differed significantly for DOMS measured when the arm was extended ( p = 0.043 ) . Significant main effects for treatment were found on the maximal force ( p = 0.026 ) , the flexion angle of the elbow ( p = 0.014 ) and the creatine kinase activity in blood ( p = 0.006 ) . No time-by-treatment interactions were found . DOMS on pressure , extension angle and myoglobin concentration in blood did not differ between the groups . This combination of a warm-up , stretching and massage reduces some negative effects of eccentric exercise , but the results are inconsistent , since some parameters were significantly affected by the treatment whereas others were not , despite the expected efficacy of a combination of treatments . The objective measures did not yield more unequivocal results than the subjective DOMS scores Research demonstrates an inverse relationship between the range of motion of selected joint movements ( flexibility ) and running economy . Since stretching exercises have been shown to increase joint range of motion , stretching exercises may be contraindicated for endurance running performance . Hence , this study investigated the influence of a 10-week program of stretching exercises on the oxygen costs of a 10 min sub-maximal ( approx . 70 % peak VO(2 ) ) treadmill run .  Thirty-two ( 16 female , 16 male ) physically active , treadmill accommo date d , college students participated in the study . All participants maintained their current activity level , with half the participants ( 8 female , 8 male ) adding a 40 min , 3 days per week session of thigh and calf muscle stretching exercises . After 10 weeks , the stretching group ( STR ) exhibited a significant ( P<0.05 ) increase ( 3.1+/-2.2 cm ) in the sit- and -reach , while the non-stretching group ( CON ) experienced no significant ( P>0.05 ) change ( 0.0+/-0.4 cm ) . However , neither the STR nor the CON exhibited a significant ( P>0.05 ) change in the O(2 ) cost for the submaximal run . It is concluded , therefore , that a chronic stretching program does not necessarily negatively influence running economy Hamstring muscle strain represents a significant injury to the athlete participating in sporting activities . Lack of hamstring flexibility has been correlated to hamstring muscle injury . There is , however , conflict concerning the most efficient hamstring stretching technique . The purpose of this study was to compare static stretch ( SS ) and proprioceptive neuromuscular facilitation ( PNF ) hamstring stretching techniques while maintaining the pelvis in two testing positions : anterior pelvic tilt ( APT ) or posterior pelvic tilt ( PPT ) . Two groups of 10 subjects were r and omly assigned to either an APT or PPT position . Each subject then performed eight sessions using PNF 
    Output:
    
There is not sufficient evidence to endorse or discontinue routine stretching before or after exercise to prevent injury among competitive or recreational athletes .