[shikoLM]

פורסם במקור על ידי VoRteX

אז רגע, אם מתיחות וחימום לא הכרחיים, אז למה הרבה פעמים בבי"ס, שיש בוחן לריצת 60 מטר, בערך באמצע הריצה ה-quads נתפס חזק מאוד?

אין שום דרך להסתמך או בכלל להגיב על האנקדוטה שהבאת. מהמחקרים עולה שאין חשיבות לחימום (בהכללה גם מתיחות) במניעת פציעות ולמתיחות כשלעצמם אין שום חשיבות כמשפרי ביצועים.
אני מצרף עוד כמה מחקרים בנושא.

Dynamic vs. static-stretching warm up: the effect on power and agility performance.

McMillian DJ, Moore JH, Hatler BS, Taylor DC.
United States Military Academy, West Point, USA. danny.mcmillian@us.army.mil
The purpose of this study was to compare the effect of a dynamic warm up (DWU) with a static-stretching warm up (SWU) on selected measures of power and agility. Thirty cadets at the United States Military Academy completed the study (14 women and 16 men, ages 18-24 years). On 3 consecutive days, subjects performed 1 of the 2 warm up routines (DWU or SWU) or performed no warm up (NWU). The 3 warm up protocols lasted 10 minutes each and were counterbalanced to avoid carryover effects. After 1-2 minutes of recovery, subjects performed 3 tests of power or agility. The order of the performance tests (T-shuttle run, underhand medicine ball throw for distance, and 5-step jump) also was counterbalanced. Repeated measures analysis of variance revealed better performance scores after the DWU for all 3 performance tests (p < 0.01), relative to the SWU and NWU. There were no significant differences between the SWU and NWU for the medicine ball throw and the T-shuttle run, but the SWU was associated with better scores on the 5-step jump (p < 0.01). Because the results of this study indicate a relative performance enhancement with the DWU, the utility of warm up routines that use static stretching as a stand-alone activity should be reassessed.
PMID: 16937960 [PubMed - indexed for MEDLINE]

Acute effects of different warm-up protocols with and without a
weighted vest on jumping performance in athletic women.

Thompsen AG, Kackley T, Palumbo MA, Faigenbaum AD.
Department of Exercise Science and Physical Education, University of Massachusetts, Boston 02125, USA.
The purpose of this study was to examine the acute effects of 3 different warm-up protocols with and without a weighted vest on vertical jump (VJ) and long jump (LJ) performance in athletic women. Sixteen subjects (19.7 +/- 1.4 years, 67.0 +/- 10.7 kg, 165.7 +/- 11.4 cm) participated in 3 testing sessions in random order on 3 nonconsecutive days. Prior to the testing of the VJ and LJ, the subjects performed 1 of the following 10-minute warm-up protocols: (a) low- to moderate-intensity stationary cycling followed by 4 lower-body static stretches (SS) (3 x 20 seconds); (b) 12 moderate- to high-intensity dynamic exercises (DY); and (c) the same 12 dynamic exercises with a weighted vest (10% of body mass) worn for the last 4 exercises (DYV). Analysis of the data revealed that VJ performance was significantly greater (p < 0.05) following DYV (43.9 +/- 6.7 cm) and DY (43.6 +/- 6.5 cm) as compared to SS (41.7 +/- 6.0 cm). Long jump performance was significantly greater (p < 0.05) following DYV (186.8 +/- 19.5 cm) as compared to DY (182.2 +/- 19.1 cm), which in turn was significantly greater (p < 0.05) than performance following SS (177.2 +/- 18.8 cm). Warm-up protocols that include dynamic exercise may be a viable method of enhancing jumping performance in athletic women as compared to stationary cycling and static stretching. In addition, these data suggest that it may be desirable for athletic women to perform dynamic exercises with a weighted vest on some movements prior to the performance of the long jump.
PMID: 17313270 [PubMed - indexed for MEDLINE]

Effects of running, static stretching and practice jumps on explosive force production and jumping performance.

Young WB, Behm DG.
School of Human Movement and Sport Sciences, University of Ballarat, Ballarat, Victoria, Australia. w.young@ballarat.edu.au
AIM: The interaction between running, stretching and practice jumps during warm-up for jumping tests has not been investigated. The purpose of the present study was to compare the effects of running, static stretching of the leg extensors and practice jumps on explosive force production and jumping performance. METHODS: Sixteen volunteers (13 male and 3 female) participated in five different warm-ups in a randomised order prior to the performance of two jumping tests. The warm-ups were control, 4 min run, static stretch, run + stretch, and run + stretch + practice jumps. After a 2 min rest, a concentric jump and a drop jump were performed, which yielded 6 variables expressing fast force production and jumping performance of the leg extensor muscles (concentric jump height, peak force, rate of force developed, drop jump height, contact time and height/time). RESULTS: Generally the stretching warm-up produced the lowest values and the run or run + stretch + jumps warm-ups produced the highest values of explosive force production. There were no significant differences (p<0.05) between the control and run + stretch warm-ups, whereas the run yielded significantly better scores than the run + stretch warm-up for drop jump height (3.2%), concentric jump height (3.4%) and peak concentric force (2.7%) and rate of force developed (15.4%). CONCLUSION: The results indicated that submaximum running and practice jumps had a positive effect whereas static stretching had a negative influence on explosive force and jumping performance. It was suggested that an alternative for static stretching should be considered in warm-ups prior to power activities.
PMID: 12629458 [PubMed - indexed for MEDLINE]



A randomized trial of preexercise stretching for prevention of lower-limb injury.

Pope RP, Herbert RD, Kirwan JD, Graham BJ.
Physiotherapy Department, Kapooka Health Centre, New South Wales, Australia. Rodney.Pope.69210450@army.defence.gov.au
PURPOSE: This study investigated the effect of muscle stretching during warm-up on the risk of exercise-related injury. METHODS: 1538 male army recruits were randomly allocated to stretch or control groups. During the ensuing 12 wk of training, both groups performed active warm-up exercises before physical training sessions. In addition, the stretch group performed one 20-s static stretch under supervision for each of six major leg muscle groups during every warm-up. The control group did not stretch. RESULTS: 333 lower-limb injuries were recorded during the training period, including 214 soft-tissue injuries. There were 158 injuries in the stretch group and 175 in the control group. There was no significant effect of preexercise stretching on all-injuries risk (hazard ratio [HR] = 0.95, 95% CI 0.77-1.18), soft-tissue injury risk (HR = 0.83, 95% CI 0.63-1.09), or bone injury risk (HR = 1.22, 95% CI 0.86-1.76). Fitness (20-m progressive shuttle run test score), age, and enlistment date all significantly predicted injury risk (P < 0.01 for each), but height, weight, and body mass index did not. CONCLUSION: A typical muscle stretching protocol performed during preexercise warm-ups does not produce clinically meaningful reductions in risk of exercise-related injury in army recruits. Fitness may be an important, modifiable risk factor.
PMID: 10694106 [PubMed - indexed for MEDLINE]

Stretching before exercise does not reduce the risk of local muscle injury: a critical review of the clinical and basic science literature.

Shrier I.
Centre for Clinical Epidemiology and Community Studies, SMBD-Jewish General Hospital, Montreal, Quebec, Canada.
OBJECTIVE: To evaluate the clinical and basic science evidence surrounding the hypothesis that stretching immediately before exercise prevents injury. DATA SOURCES AND SELECTION: MEDLINE was searched using MEDLINE subject headings (MeSH) and textwords for English- and French-language articles related to stretching and muscle injury. Additional references were reviewed from the bibliographies, and from citation searches on key articles. All articles related to stretching and injury or pathophysiology of muscle injury were reviewed. Clinical articles without a control group were excluded. RESULTS: Three (all prospective) of the four clinical articles that suggested stretching was beneficial included a cointervention of warm-up. The fourth study (cross-sectional) found stretching was associated with less groin/buttock problems in cyclists, but only in women. There were five studies suggesting no difference in injury rates between stretchers and nonstretchers (3 prospective, 2 cross-sectional) and three suggesting stretching was detrimental (all cross-sectional). The review of the basic science literature suggested five reasons why stretching before exercise would not prevent injuries. First, in animals, immobilization or heating-induced increases in muscle compliance cause tissues to rupture more easily. Second, stretching before exercise should have no effect for activities in which excessive muscle length is not an issue (e.g., jogging). Third, stretching won't affect muscle compliance during eccentric activity, when most strains are believed to occur. Fourth, stretching can produce damage at the cytoskeleton level. Fifth, stretching appears to mask muscle pain in humans. CONCLUSION: The basic science literature supports the epidemiologic evidence that stretching before exercise does not reduce the risk of injury.
PMID: 10593217 [PubMed - indexed for MEDLINE]

Prevention of running injuries by warm-up, cool-down, and stretching exercises.

van Mechelen W, Hlobil H, Kemper HC, Voorn WJ, de Jongh HR.
Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
The purpose of this study was to evaluate the effect of a health education intervention on running injuries. The intervention consisted of information on, and the subsequent performance of, standardized warm-up, cool-down, and stretching exercises. Four hundred twenty-one male recreational runners were matched for age, weekly running distance, and general knowledge of preventing sports injuries. They were randomly split into an intervention and a control group: 167 control and 159 intervention subjects participated throughout the study. During the 16-week study, both groups kept a daily diary on their running distance and time, and reported all injuries. In addition, the intervention group was asked to note compliance with the standardized program. At the end of the study period, knowledge and attitude were again measured. There were 23 injuries in the control group and 26 in the intervention group. Injury incidence for control and intervention subjects was 4.9 and 5.5 running injuries per 1000 hours, respectively. The intervention was not effective in reducing the number of running injuries; it proved significantly effective (P < 0.05) in improving specific knowledge of warm-up and cool-down techniques in the intervention group. This positive change can perhaps be regarded as a first step on the way to a change of behavior, which may eventually lead to a reduction of running injuries.
PMID: 8238713 [PubMed - indexed for MEDLINE]