Quick Hit Summary

Static stretching was once a staple part of most pre workout warm-ups. However, during recent years it has fallen out of favor as various studies have shown it to decrease physical capabilities when performed immediately prior to exercise performance testing. Yet, WHEN FOLLOWED with a dynamic warm up and spaced far enough in advance of the actual lifting/running portion of the workout, this detrimental effect is not observed in the literature. Thus, combined with its role in reducing muscle strains, it may be advantageous to complete a routine that is conducted in the following order: Light aerobic activity —> Static Stretching —> Dynamic warm-up exercises —> main workout.

Pre Workout Warm-ups & Static Stretching

Figure 1 Don’t “kill” your workouts before you even start them. If you’re going to static stretch, follow it up with dynamic movements prior to competing!!! Source.²⁶

The warm-up is a critical component of any productive exercise session. The inclusion of a properly completed warm-up decreases the risk of injury while simultaneously enhancing muscular performance¹². One of the key components of many warm-up programs is static stretching which involves holding a muscle in a stretched position for a given amount of time, 6-30+ seconds, before relaxing out of it. Although it’s role in injury prevention is debated, there is some evidence to indicate that static stretching may reduce the likelihood of muscle strains.³ (Refer to the last section of this article for further discussion on the static stretch – injury debate).

However, 10-15 years ago (late 90’s, early ’00), the role of pre-workout static stretching came into question. This largely stemmed from research demonstrating that static stretching increased muscle-tendon compliancy (ie – less stiff muscles & tendons) and decreased muscle “excitability”, thus reducing muscle force capabilities⁴. This was best demonstrated in a study completed by Fowles et al⁵. In their investigation, researchers had 10 individuals (6 men, 4 women) complete a static stretching protocol that consisted of 13 plantar flexor stretches, each lasting 135 s in duration, over a 33 minute time span. (For reference, this would be stretching the muscles on the front part of your lower leg. One stretches these muscles when they point their toes away from them). The subjects were instructed to hold the static stretches at a maximum tolerable intensity level. Results are shown in Figure 2. As you can see, immediately following the completion of the stretching protocol, isometric strength capabilities of the plantar flexor muscles decreased 28% vs. that of the control condition. Even after 60 minutes, researchers still observed a statistically significant reduction in muscle force production (9%).

Figure 2. Decrease in muscle force production following static stretching vs. no stretch condition. All time points were significantly reduced vs control condition. For reference, muscle force production was determined via Maximal Voluntary Isometric Contractions (MVIC). For a more detailed explanation of MVIC read the first section of the article Training Muscles Before Movements. Figure created by Sean Casey. Data adapted from Fowles et al⁵.

Static Stretching Performed Immediately Prior to Athletic test

Aneorobic Performance Testing

Taking a step back from the laboratory setting and looking at more “real life” athletic skills, researchers have found that static stretching, performed immediately prior to exercise, has lead to decreased aneorobic strength and power. Fletcher and colleagues, found it to decrease vertical jump performance by ~ 1 inch (2.54 cm)⁷. Likewise, Winchester et al found it to increase 40 meter dash times by 0.10 seconds⁸. In a latter study completed by Winchester et al., researchers found that a 1×30 seconds of statically stretching both hamstrings decreased leg curl 1RM by 5.4% and, when repeated 6x, led to a 12.4% reduction in performance⁹.

Aerobic Performance testing

With respect to aerobic based activity, Wilson et al. found that 16 minutes of static stretching had detrimental effects on subsequent endurance running performance. In comparison to control conditions (quiet rest), their research team found that static stretching reduced the total distance covered during a 30 minute run by 0.2 km.¹⁰ Although a difference of 0.2 kilometers might not seem like a lot, this is a huge margin. For example, at the 2008 men’s Olympic 10,000 km race most runners completed the race between 27-28 minutes (although not quite 30 minutes, close enough for our purposes). If the 2nd place runner was 0.2 km behind the winner, it would mean that the winner won by ~½ the length of the track.

Should we completely ditch the use of static stretching from our warm-up?

After reading the research presented above, you may be thinking that we should completely eliminate static stretching from our warm-up. I must be honest… For a while, I said “yes” to this idea. However, a little while back, my thoughts regarding this were challenged in an article by Ian King entitled, “The Lazy Man’s Guide to Stretching – 15 minutes to (joint) freedom!”. Ian has long used static stretching in his athletes training programs with success (Check out the “Ian’s Training Myths” portion of my interview with him). Thus, I was forced to re-evaluate my opinion and thoughts on the subject…

I went back through the scientific literature with a careful eye. In doing so, I found one HUGE caveat… Most of the commonly cited studies that have shown decreased muscular performance included only static stretching in their warm-up routine or it was performed just prior to performance testing. Yet, this differs considerably vs. that done by many athletes who static stretch, perform a dynamic warm-up to activate specific muscle groups and then start participating in a given activity. Thus the question remains, “Does a warm-up that includes static stretching followed by dynamic warm-up exercises impair physical performance?”

Sport Athletes – Maximum Strength

Molacek and colleagues investigated the effects of various pre workout stretching routines on bench press 1RM¹¹. In the study, 15 male collegiate football players had their bench press 1RM tested 5x over the course of 3 weeks. Lifting sessions were exactly the same, differing only in the type of stretching completed pre-workout:

1st warm-up set (5-10 reps at 40-60% 1RM—> randomly ordered stretching routine (see below) —> 2nd warm-up set (60-80% 1RM) —> 1RM testing

• No stretch
• Low Volume Static stretching (LVSS): 1 chest and 1 triceps stretch, 2×20s
• High Volume Static stretching (HVSS): 1 chest and 1 triceps stretch, 5×30s
• Low Volume PNF stretching (LVPNF): 1 chest and 1 triceps stretch, 2× 5s-10s-10s (5 resisted contraction at point of stretch, 10 seconds relaxation, 10 seconds of passive stretch)
• High Volume PNF stretching (HVPNF): 1 chest and 1 triceps stretch, 5× 5s-10s-10s (5 resisted contraction at point of stretch, 10 seconds relaxation, 10 seconds of passive stretch)

As seen above, following each of the stretching protocols, athletes completed another warm-up set of bench press (3-5 reps at 60-80% 1RM), rested for up to 5 minutes, and then completed the 1 RM testing protocol¹¹. Upon completion of the study, the mean results for each testing session were compared to one another. As seen in Figure 2, Molacek et al found no significant differences between trials; the mean max bench press following each session was ~284 +/- 1.5 lbs (129 +/- 0.7 kg).*

Figure 2. Effects of various stretching protocols on 1RM bench press performance. No statistically significant differences were observed between trials. LVSS = Low Volume Static stretching, High Volume Static stretching (HVSS), Low Volume PNF stretching (LVPNF), High Volume PNF stretching (HVPNF). Data adapted from Molacek et al.¹¹

Recreational Exercisers – Maximum Strength

Beedle et al examined the effects of light static stretching on bench and leg press 1RM in 51 college aged individuals participating in a weight training class²⁹. On three different occasions, separated by 72 hours, individuals partook in one of the following warm-up protocols:

Randomly ordered static or dynamic stretching (see below) —> 1st warm up set (6 reps at 40-60% of perceived 1RM) —> 2nd warm up set (6 reps at 60-80% of perceived 1RM) —> Performance testing

• Control
• Static Stretch: 2 upper body, 2 lower body, 3×15 seconds
• Dynamic stretch: Arm and Leg Swings, 3×30 seconds

Upon completing all 3 sessions, the research team compared results. Beedle et al. found that irregardless of the type of stretching one completed during the warm-up 1RM for both the bench and leg press were unaffected.²⁹ In other words, static stretching did not significantly impair performance. This held true for both men and women.

Sport Athletes – Sport Skill Performance (Sprints, Jumps, Agility)

Taylor et al. found a lack of effect of static stretching on exercise performance when skill specific movement skills were incorporated into a warm-up¹². In their study 13 netball players from the Australian Institute of Sport completed 2 separate testing sessions that consisted of the following protocol:

Light jog —> static or dynamic stretching —> vertical jump and 20 meter sprint test —> netball specific skill warm-up (SKILL) —> vertical jump (VJ) and 20 meter sprint re-test.

The static stretching involved 1-2 sets of 9 lower body stretches; each held for 30 seconds¹². By performing 2 separate vertical and sprint tests in each testing session, researchers were able to assess the impact of skill specific warm-up post static stretching. Although differences were present during the first test (static stretching decreased VJ by 4.2%, sprint 1.4% vs. dynamic); researchers found that when tested after a skill specific warm-up, there were no significant differences in performance between the two warm-up protocols.

Looking at a different population of athletes, Gelen had 26 professional male soccer players complete 4 different warm-ups, each followed by 3 soccer specific skill tests (30 meter sprint speed, slalom dribble, and penalty kick ball speed)¹³. The four sessions, completed over an 11 day period, went as follows:

5 min light jog —> 2 min walk —> randomly ordered stretching routine (see below) —> 5 minutes —> skill testing

• Quiet Rest (QR) – 4-5 minutes
• Static Stretch (SS) – 5 lower body stretches; 20 second stretch, 10 seconds relaxation, 30 seconds more stretch
• Dynamic Exercise (DE) – 12 dynamic exercises (Walking lunges, A & B skips, Carioca, etc); 2 sets of 15 yards each
• Static Stretch followed by Dynamic Exercise (SSDE)

As to be expected, based off the research presented at the start of this article, Gelen found that the completion of only static stretching led to a statistically significant decrease in performance¹³. The DE condition significantly improved both sprint (4.9%), slalom dribbling (5.1%) and penalty kick speed (3.3%) vs. QR, whereas the SSDE neither inhibited nor enhanced performance vs. QR, SS or DE conditions (see Figure 3 for sprint and slalom speed).

Figure 3. 30 meter sprint and slalom dribbling speed following various of warmup protocols. QR = Quiet Rest, SS = Static Stretching, DE = Dynamic Exercise, SSDE = Static Stretch + Dynamic Exercise. Stars (*) signify significantly different vs. QR condition. Data adapted from Gelen¹³.

In a very complex study carried out by Chaouachi and colleagues, involving 22 highly trained males, researchers compared the effect of 8 different warm-up protocols on 30 meter sprints, agility t-tests, and various jump tests (squat jump, counter-movement jump and a 5 jump horizontal test)¹⁴. The warm up protocol involved the following layout:

5 min light aerobic activity —> 10 minutes of a randomly ordered stretching protocol (see below) —> 5-7 minutes of incrementally increasing explosive skill exercises (bounds, 30 meter build up runs, agility runs at 3/4 pace, etc) —> 2 minute recovery —> Performance testing.

• Control – quiet rest
• Static stretch to point of discomfort (SS = POD); 5 lower body stretches, 2×30 seconds
• SS to 90% POD (SS < POD)
• Dynamic stretching (DS); 5 lower body stretches, 2×30 seconds
• SS = POD followed by DS; 1 set of each dynamic and static stretch <— same for all combined conditions
• SS < POD followed by DS
• DS followed by SS = POD
• DS followed by SS < POD

Over a 16 day period, each athlete completed all 8 of the warm-up protocols in a randomized order; ~ 48 hours of rest were between each test session¹⁴. At the conclusion of the study, with an exception of a couple minor statistical differences, researchers failed to find any significant differences between warm-up protocols and the ensuing exercise tests (30 meter sprints, agility t-tests, and squat, counter-movement and a 5 jump horizontal test). There are a few particular things that I like about this study which are worth pointing out. First, as you can see, Chaouachi and colleagues did not leave much to question as virtually every stretching variable was examined (dynamic vs. static, order of dynamic vs. static, intensity of stretch —> 90% POD vs. POD). Furthermore, all warm-ups concluded with 5-7 minutes of movements that incrementally increased in intensity, similar to that observed with sporting athletes.,

Sim et al also found that when followed by dynamic exercises, which incrementally increased in intensity, static stretching did not negatively affect repeated sprint performance¹⁵. For reference, their study population included 13 male team sport athletes (soccer, rugby, Australian football) with a mean age of 24 years. Also, 4 different lower body static stretches were completed, 2×20 seconds.

An Exception to the Rule in Trained Athletes… With a Caveat

Although the aforementioned studies in this section have indicated that a static stretch, followed by a dynamic exercise warm-up, does not have a detrimental effect on subsequent exercise performance, there has been one exception to my knowledge. In a study involving 18 sprinters (10 men: 19 years old, best 100 meter times -10.69s & 8 women: 20 years old, best 100 meter time – 12.05s), Fletcher & Anness examined the effects of the following 3 warm-up protocols¹⁶:

800 meter jog —> randomly ordered stretching routine (see below) —> 2 × 50m runs at 80% max velocity (4 min) —> 50 meter sprint test

• Active Dynamic Warm-up Exercises (ADE): 2× 20 meters of 5 exercises (straight leg skips, walking high knees, skipping high knees, running high knees, flip backs)
• Static Stretch + Active dynamic warm-up exercises (SSADE): 5 lower body stretches, 3×22 seconds
• Dynamic Stretches +Active Dynamic Warm-up exercises (DADE): 5 dynamic stretches, 2×8 reps/leg.

Upon the completion of all 3 testing sessions, Fletcher and Anness found that static stretching, even when followed by a dynamic warm-up exercises, significantly increased sprint times vs. both the ADE (males – 0.16s, females – 0.10 s) and DADE (males – 0.11s, females – 0.09s) conditions. Similar results were seen in both male and females as shown in Figure 4. A potential reason as to why the results of Fletcher and Anness¹⁶ differs from that observed by Chaouachi et al¹⁴ may be related to the time between the static stretching and ensuing exercise testing took place. In this latter study, there was ~ 20 minutes between the completion of the static stretching and sprint testing¹⁴ whereas in the former study, only 5-7+ minutes where present between the two time points¹⁶.

Figure 4. 50 meter Sprint Times After 3 different Warm-up Protocols. ADE = Active Dynamic Warm-up Exercises, DADE = Dynamic Stretches +Active Dynamic Warm-up exercises, SSADE = Static Stretch + Active dynamic warm-up exercises. Stars (*) signify significantly different vs. other conditions. Data adapted from Fletcher and Anness¹⁶

Recreational Exercises – Sport Skill Performance (Sprints, Jumps, Agility)

To my knowledge, as of June 2011, there has only been one study carried out in recreational athletes that have assessed the effects of static stretching, followed by dynamic warm-up exercises, on ensuing anaerobic performance. The study, completed by Vetter, looked the effects of various warm-up protocols on 30 meter sprint and counter movement jump performance in 26 college age recreational exercisers (14 men, 12 women).¹⁷ “Recreational” was defined as exercising a minimum of 30 minutes 3-5x/week. On 6 separate occasions, subjects completed one of the following warm-ups:

4 minute walk —> 2 minute run —> randomly ordered stretching routine (see below) —> 30 meter sprint counter movement jump test

• Control
• Static Stretch (SS):4 lower body stretches, 2×30 seconds
• Warm-up Exercises +Small jumps (EJ): 4 dynamic exercises (toe raises -10x, marching butt kicks -20 steps, butt kicks – 20 steps, 10 mini-jumps), Repeat 3x
• Dynamic Active Stretch (DA): 4 lower body exercises, 8 reps/limb
• SS followed by EJ (SSEJ)
• DA followed by EJ (DAEJ)

All protocols were completed over a 14 day period, with 48-72 hours of recovery¹⁷. In comparing results, no significant differences were found between any of the conditions except for SS only condition which decreased vertical jump performance vs. WR (~ 1%) and DAEJ (~1%). No significant differences were noted between any of the sprint conditions. Additionally, although men had higher jumps and faster sprint times vs. the women, they responded similarly to with respect to the effect of warm-up on ensuing exercise performance. In summary, when static stretching was followed by dynamic warm-up exercises, jump and sprint performance was unaffected in both men and women.

Aerobic Performance

To the best of my knowledge, there has not been any research that has examined aerobic exercise performance on either recreational or high level aerobic athletes that has used a warm-up protocol as follows: light warm-up —> static stretching —> dynamic warm-up exercises —> Aerobic testing.

Order of a Warm-up

On a final note, I’d like to mention a couple of things. First, I’d like to point out that the static stretching in the studies mentioned in the previous section were all proceeded by a light aerobic activity of some sorts (jog, etc) . Thus, the order of the warm-up proceeded as follows: light jog —> static stretching —> dynamic warm-up exercises —> physical performance tests. Also, I wouldn’t recommend reverse the order such that the dynamic warm-up exercises precedes the static stretching component of the workout. Although it wasn’t observed by Chaouachi et al¹⁴, various research groups have found that static stretching, after a dynamic warmup, without any reactivation of the targeted muscle groups, has decreased sprint performance¹⁸¹⁹.

Static Stretching and Injury Risk

So far I’ve presented multiple studies which have demonstrated that static stretching, when followed by dynamic warm up exercises, does not negatively affect exercise performance. The one caveat to this was the study completed Fletcher and Anness¹⁶, which may have been related to the short interval between the completion of the static stretching and the start of exercise testing. Yes this is all interesting, but the time pressed inquisitive mind may be asking…

”OK, I agree with you that pre-workout static stretching doesn’t limit exercise performance if followed with some dynamic warm-up stuff. However, static stretching + dynamic warm-up exercises did not lead to greater physical performance vs. dynamic alone. Thus, if it doesn’t increase physical performance, are we just wasting our time?”

(Please notice how I stress pre-workout static stretching. A dedicated training session, focused entirely on stretching, and its role in athletic development, could be a full article in and of itself!).

In a large review of the literature, McHugh and Cosgrave present evidence that although pre-exercise static stretching may not reduce the likelihood of developing chronic injuries, its inclusion may reduce the incidence of muscle strains for the following reason²⁰:

“stretching makes the muscle–tendon unit more compliant … increased compliance shifts the angle–torque relationship to allow greater relative force production at longer muscle lengths … Subsequently the enhanced ability to resist excessive muscle elongation may decrease the susceptibility to a muscle strain injury.”²⁰

Theory is all fine and dandy, but is there any evidence, outside of anecdotal, to support the idea that static stretching may reduce muscle strains? Unfortunately, this is an area that few researchers have examined via true randomized clinical controlled trial – the “gold” standard of research (Check out the EXPERIMENTAL STUDIES section of THIS ARTICLE if you need help brushing up on this type of study). Furthermore, of the studies that have been performed in this area, confounding factors are present.

With that in mind, there have been a few studies of note… In a group of 901 male military recruits, Amako et al found that pre-workout static stretching (18 different stretches: 4 upper body, 7 trunk, 7 lower body; 1×30s) significantly reduced the likelihood of developing a muscle /tendon injury vs. control group (2.5% vs. 6.9%)²¹. In a multi-year study, Halada and Barrios found that the addition of static stretching program (10 different stretches) from year 1 to year 2 resulted in a 82% decrease in muscle injuries (22 vs. 4) in elite yachting crews, who were participating in the American Cup²². For reference ~30 sailors took part in the study each year. A final study of note, involving soccer athletes, showed a 74% reduction in muscle injuries for those who included 10 minutes of static stretching in their warm-ups vs. the control group.²³ Although a few methodological issues are present in these studies, which makes firm conclusions hard to draw, it does provide evidence that pre-workout/competition static stretching may reduce muscle strains.

Looking at the static stretching & injury debate from the eyes of coach vs. researcher, I’d like to mention one common sense idea to keep in mind… injuries often occur as a result of flexibility imbalances. If certain muscles on your body are overly tight, your range of motion will be compromised, one’s natural motor program altered, all of which sets one up for disaster. Playing the devil’s advocate I could point to research indicating no relationship between flexibility and muscle strain²⁴. However, other studies have shown that reduced static flexibility increases the risk of muscle strains²⁵²⁶. Besides, as pointed out by McHugh and Cosgrave…

Several studies have shown that flexibility is not a significant intrinsic risk factor for muscle strain in various sports…but this is not synonymous with concluding that stretching does not prevent muscle strains.³

Furthermore, many sports require static flexibility (ie- wresting, gymnastics, etc). Obviously, if one lacks the flexibility to get into the specific static positions required for maximum effectiveness, his/her performance will suffer. In order to acquire this range of motion, research as well as personal experience, indicates that static stretching is a more effective means to achieve this result vs. dynamic flexibility training alone²⁷²⁸.

Bottom Line

During the last 10-15 years, the inclusion of static stretching in one’s warm-up has been highly criticized, largely stemming from research that has shown it to decrease muscular performance. However, when one looks at the research with a careful eye, you’ll notice one big caveat; Most of these studies included static stretching only or a protocol that consisted of dynamic warm-up —> static stretching —> physical performance tests. Yet, this varies considerably vs. how many sport athletes warm-up. Taken into account the role that static stretching appears to have on muscle strains, a warm-up consisting of the following protocol may optimize performance and longevity:

Light aerobic exercise —> static stretching —> dynamic/skill specific warm-up exercises —> sporting/training activity

Thus, if an individual is willing to take the time necessary to complete a thorough warm-up, he/she may benefit from including some static stretching. However, I would not recommend static stretching immediately prior to competition without also including dynamic movements to “activate” the preferred movement patterns needed to succeed in your respective training/competition. Also, one may want to leave 7-10+ minutes between the conclusion of static stretching and start of athletic competition…. a time span which would be perfect to complete some dynamic warm-up exercises!

References

¹ Fradkin AJ, Zazryn TR, Smoliga JM. Effects of warming-up on physical performance: a systematic review with meta-analysis. J Strength Cond Res. 2010 Jan;24(1):140-8. J Strength Cond Res. 2010 Jan;24(1):140-8.

² Fradkin AJ, Gabbe BJ, Cameron PA. Does warming up prevent injury in sport? The evidence from randomised controlled trials? J Sci Med Sport. 2006 Jun;9(3):214-20. Epub 2006 May 6.

³ McHugh MP, Cosgrave CH. To stretch or not to stretch: the role of stretching in injury prevention and performance. Scand J Med Sci Sports. 2010 Apr;20(2):169-81. Epub 2009 Dec 18.

⁴ Behm DG, Chaouachi A. A review of the acute effects of static and dynamic stretching on performance. Eur J Appl Physiol. 2011 Mar 4. [Epub ahead of print]

⁵ Fowles, JR, Sale, DG, and MacDougall, JD. Reduced strength after passive stretch of the human plantarflexors. J Appl Physiol 89: 1179–1188, 2000.

⁶ Power K, Behm D, Cahill F, Carroll M, Young W. An acute bout of static stretching: effects on force and jumping performance. Med Sci Sports Exerc. 2004 Aug;36(8):1389-96.

⁷ Fletcher IM, Monte-Colombo MM. An investigation into the effects of different warm-up modalities on specific motor skills related to soccer performance. J Strength Cond Res. 2010 Aug;24(8):2096-101.

⁸ Winchester JB, Nelson AG, Landin D, Young MA, Schexnayder IC. Static stretching impairs sprint performance in collegiate track and field athletes. J Strength Cond Res. 2008 Jan;22(1):13-9.

⁹ Winchester JB, Nelson AG, Kokkonen J. A single 30-s stretch is sufficient to inhibit maximal voluntary strength. Res Q Exerc Sport. 2009 Jun;80(2):257-61.

¹⁰ Wilson JM, Hornbuckle LM, Kim JS, Ugrinowitch C, Lee SR, Zoundos MC, Sommer B, Panton LB.Effects of Static Stretching on Energy Cost and Running Endurance Performance. J Strength Cond Res. 2009 Nov.

¹¹ Molacek ZD, Conley DS, Evetovich TK, Hinnerichs KR. Effects of low- and high-volume stretching on bench press performance in collegiate football players. J Strength Cond Res. 2010 Mar;24(3):711-6.

¹² Taylor KL, Sheppard JM, Lee H, Plummer N. Negative effect of static stretching restored when combined with a sport specific warm-up component. J Sci Med Sport. 2009 Nov;12(6):657-61. Epub 2008 Sep 3.

¹³ Gelen E. Acute effects of different warm-up methods on sprint, slalom dribbling, and penalty kick performance in soccer players. J Strength Cond Res. 2010 Apr;24(4):950-6.

¹⁴ Chaouachi A, Castagna C, Chtara M, Brughelli M, Turki O, Galy O, Chamari K, Behm DG. Effect of warm-ups involving static or dynamic stretching on agility, sprinting, and jumping performance in trained individuals. J Strength Cond Res. 2010 Aug;24(8):2001-11.

¹⁵ Sim AY, Dawson BT, Guelfi KJ, Wallman KE, Young WB.Effects of static stretching in warm-up on repeated sprint performance. J Strength Cond Res. 2009 Oct;23(7):2155-62.

¹⁶ Fletcher IM, Anness R. The acute effects of combined static and dynamic stretch protocols on fifty-meter sprint performance in track-and-field athletes. J Strength Cond Res. 2007 Aug;21(3):784-7.

¹⁷ Vetter RE. Effects of six warm-up protocols on sprint and jump performance. . J Strength Cond Res. 2007 Aug;21(3):819-23.

¹⁸ Kistler BM, Walsh MS, Horn TS, Cox RH. The acute effects of static stretching on the sprint performance of collegiate men in the 60- and 100-m dash after a dynamic warm-up. J Strength Cond Res. 2010 Sep;24(9):2280-4.

¹⁹ Winchester JB, Nelson AG, Landin D, Young MA, Schexnayder IC.
Static stretching impairs sprint performance in collegiate track and field athletes. J Strength Cond Res. 2008 Jan;22(1):13-9.

²⁰ Behm DG, Chaouachi A. A review of the acute effects of static and dynamic stretching on performance. Eur J Appl Physiol. 2011 Mar 4. [Epub ahead of print]

²¹ Amako M, Oda T, Masuoka K, Yokoi H, Campisi P. Effect of static stretching on prevention of injuries for military recruits. Mil Med. 2003 Jun;168(6):442-6.

²² Hadala M, Barrios C. Different strategies for sports injury prevention in an America’s Cup Yachting Crew. Med Sci Sports Exerc 2009: 41: 1587–1596.

²³ Ekstrand J, Gillquist J, Liljedahl SO. Prevention of soccer injuries.Supervision by doctor and physiotherapist. Am J Sports Med 1983: 11: 116–120.

²⁴ Tyler TF, Nicholas SJ, Campbell RJ, McHugh MP.The association of hip strength and flexibility with the incidence of adductor muscle strains in professional ice hockey players. Am J Sports Med. 2001 Mar-Apr;29(2):124-8.

²⁵ Witvrouw E, Danneels L, Asselman P, D’Have T, Cambier D. Muscle flexibility as a risk factor for developing muscle injuries in male professional soccer players. A prospective study. Am J Sports Med. 2003 Jan-Feb;31(1):41-6.

²⁶ Bradley PS, Portas MD. The relationship between preseason range of motion and muscle strain injury in elite soccer players. J Strength Cond Res. 2007 Nov;21(4):1155-9.

²⁷ Bandy WD, Irion JM, Briggler M. The effect of static stretch and dynamic range of motion training on the flexibility of the hamstring muscles. J Orthop Sports Phys Ther. 1998 Apr;27(4):295-300.

²⁸ O’Sullivan K, Murray E, Sainsbury D (2009) The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects. BMC Musculoskelet Disord 10:37–42

²⁹ Beedle B, Rytter SJ, Healy RC, Ward TR. Pretesting static and dynamic stretching does not affect maximal strength. J Strength Cond Res. 2008 Nov;22(6):1838-43.

³⁰ Image courtesy of SuperFantastic. Uploaded by Accessed June 14, 2010 from:flickr.com/photos/35423169@N00/3883868105