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Potential Effects of Dynamic Stretching on Injury Incidence of Athletes: A Narrative Review of Risk Factors

Behm, D.G., Alizadeh, S., Daneshjoo, A. and Konrad, A., 2023. Potential Effects of Dynamic Stretching on Injury Incidence of Athletes: A Narrative Review of Risk Factors. Sports Medicine, pp.1-15

In today’s letter

• Overview of the Potential Effects of Dynamic Stretching on Injury Incidents

• Clinical tips to help you in your practice right away

• Resources to teach you more about dynamic warm ups

• Rapid Results =

This narrative review concludes that dynamic stretching may have beneficial effects on:

• Knee kinematics

• The muscle-tendon junction morphology

• Athletes’ readiness to compete

but not on: ROM, performance & balance/proprioception

• Professional takeaway =

The benefits outweigh the risks of dynamic stretching, thus no reason not to include it in practice.

Aim of the study

• The aim of this narrative review was to examine existing research on injury rates when dynamic stretching is included in a warm-up routine before activity.

• Additionally, the authors looked into potential factors that could influence these injury rates, including ROM, strength, balance, proprioception, muscle structure, and psychophysiological responses. 

Did you know?

There’s long been debate around stretching and its effect on performance, particularly when comparing static and dynamic stretching.

For many years It’s been suggested that static stretching can negatively influence performance in both the stretched muscle and the opposite, non-stretched muscle group.

However, previous reviews and original research indicate that when static stretching is kept brief (no more than 60 seconds per muscle group) and performed as part of a complete warm-up routine, its negative effects are minimal.

What that means is..

When static stretching follows aerobic activation and is then followed by dynamic movements and sport-specific drills, performance is generally unaffected.

Dynamic stretching, on the other hand, involves controlled, repetitive movements that take the muscle through its active range of motion.

It alternates between muscle tension at the end range and relaxation through the mid-range, preparing the muscle-tendon unit for explosive movement patterns.

 Methods

Interestingly, the authors found only two studies that specifically examined how dynamic stretching alone affects injury occurrence.

Because of this limited number, a systematic review or meta-analysis wasn’t possible.

Instead, they opted for a narrative review, which allowed them to look into a broader scope of information without being restricted by the rigid structure typically required in systematic methodologies.

This approach gave flexibility to discuss findings and trends that might otherwise be excluded.

So, How Do Dynamic Warm-Ups Help?

Range of Motion

As with many things within sports medicine there’s still debate about how flexibility or a lack thereof relates to injury risk.

That being said,

The majority of research suggests that dynamic stretching can increase range of motion and flexibility. However, as mentioned above evidence is mixed regarding whether limited flexibility directly increases injury risk

In short…

Based on current evidence, dynamic stretching can be beneficial for improving flexibility and should be incorporated into warm-ups using moderate intensity.

However, excessive or overly intense stretching should be avoided to prevent potential decreases in ROM.

Kinematics

Another important area of research focuses on kinematics (how the body moves)

Understanding how dynamic stretching influences movement patterns is valuable because movement mechanics have been closely linked to injury risk, particularly in the lower limbs.

While most research has looked into how dynamic stretching affects flexibility or ROM, a few studies have gone a step further to look at how it changes lower limb movement during sports specific drills like kicking or landing.

Evidence suggests that dynamic stretching can alter knee motion during landings, reducing both abduction (sideways movement) and internal rotation (inward twisting).

These changes could theoretically reduce strain and injury risk.

However, the exact mechanisms is not clear, and while the current research points to a generally positive influence on joint movement, more studies are needed to confirm these effects across different types tasks.

Effects of Dynamic Stretching on Performance

Dynamic stretching appears to prepare muscles and tendons to handle forces more effectively, which may lower the risk of injuries occurring at those vulnerable points.

A meta-analysis covering 20 studies found that a single session of dynamic stretching produced small but meaningful improvements in performance across jumping, sprinting, agility, and strength testing.

However, the findings weren’t uniform: 21 studies reported trivial effects, and 7 showed impaired performance.

On average, the overall improvement was modest, around 1.3%.

The improvements seen in some studies are likely linked to several physiological factors.

1. Dynamic stretching increases muscle and body temperature, which elevates energy production.

2. It also improves neuromuscular function by influencing spindle reflexes and motor neurons, stimulating the nervous system, and reducing inhibition from opposing muscles.

3. Post-activation potentiation (the enhanced contractile response after prior activation) may also increase contraction speed.

Many of these benefits can also occur even when movements are performed through a smaller range of motion, which raises a question whether full-range dynamic stretching is necessary to achieve performance benefits.

Balance & Proprioception

Balance and proprioception are important systems when it comes to injury prevention, and both are known to be impaired when injury risk increases.

Two studies (Study 1 & study 2) investigating a single session of dynamic stretching found slight improvements in balance when participants stretched muscles like the quadriceps, hip flexors, gastrocnemius, and hamstrings before performing tests such as the Y-Balance and Star Excursion Tests.

However, not all studies agree… Shocking!

When dynamic stretching was applied to both upper and lower limbs and balance was assessed using a stability platform, no significant effects were found.

Similarly, another study focusing on the quadriceps, hamstrings, and gastrocnemius reported no changes in balance when evaluating centre of pressure during a demi-pointe pose.

Overall, the immediate effects of dynamic stretching on balance and proprioception are unclear. The results so far are mixed and murky.

Morphology

Dynamic stretching may influence muscle-tendon morphology in ways that could reduce injury risk, primarily by decreasing stiffness at the muscle-tendon junction (MTJ).

When the MTJ becomes more compliant, it can better absorb energy during explosive movement, which might also lessen post-exercise soreness.

Some researchers propose that the short-term improvements in ROM seen after dynamic stretching result more from increased stretch or pain tolerance rather than an actual change in tissue stiffness.

Over time, however, long term dynamic stretching may lead to increased MTJ compliance, shifting the angle-torque relationship.

This means that muscles could generate relatively greater force even when lengthened, an adaptation that could help protect against strain injuries, since many injuries occur when muscles are stretched beyond their optimal length.

That said, findings in this area are inconsistent. Some studies report that dynamic stretching decreases stiffness, others show no change, and a few even report increased stiffness.

Once again…

Because of these conflicting results, it’s difficult to make definitive claims about how dynamic stretching affects MTJ stiffness or whether these changes directly contribute to injury prevention.

Psychological Factors

Looking past the physical benefits, dynamic stretching can also support athletes psychologically.

Completing dynamic warm-ups should in theory positively influence mood and focus, reducing stress and improving mental readiness before competition.

These psychological benefits could help:

• Lower muscle tension

• Increase concentration

• Prepare the body and mind for performance.

Clinical Tips

• Notably, injury risk reduction hinges on raising body temperature and the activation of the nervous system to put it simply. No matter whether you’re in a clinic doing rehab or with your athletes pre training or game, the raise in body temperature will always be your primary goal.

• Established protocols like FIFA11+ have demonstrated efficacy in reducing injuries among football players and thus can be a good guide for developing simpler plans (FIFA11+ takes about 25min to complete)

Top Resources to Check Out

And learn more about dynamic stretching

1. The Fifa-11 warm up (pdf) - LINK

2. Principles of flexibility (lecture)

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When You’re Ready to Learn More

We have great resources for you to devourer

1. Killer Articles —> Literally everything you need to know about a specific injury

2. Tendinopathy 4 phase rehab frame work - My book that walks you through a step by step process of treating tendons

3. Tendininopathy Specific Guides - Learn how to diagnose, manage & treat patellar, achilees and shoulder tendinopathies