Hamstring Injury Risk Factors: How Asymmetry and Ankle Mobility Play a Role

Hamstring injuries are among the most common—and commonly misunderstood—sports injuries. But did you know that athletes with multiple movement deficits are 17 times more likely to suffer time-loss injuries? (Lehr, ME, 2013). In this post, we explore the top hamstring injury risk factors—including one you might be overlooking: the opposite side of the body.

When Jordan Ridley suffered another hamstring injury in the recent clash between North Melbourne and Essendon, it raised more than eyebrows—it raised questions. Yet Essendon coach Brad Scott was quick to brush aside any connection between Ridley's current and previous injury to the other leg, telling reporters they were “unrelated” [1].

But are they really unrelated? Or are we missing hidden links—connections that span across the body, far from the site of injury?

As a sports physiotherapist working with elite athletes, I’ve come to see patterns that suggest hamstring injuries, especially recurrent or opposite-side injuries, aren’t isolated incidents - the regionally interdepent and multi-factorial risks are often overlooked. Instead, they’re part of a bigger biomechanical and neuromuscular story.

“The hamstring is not independent of what’s above and below—it’s interdependent through the whole region.”

This principle of regional interdependence—the idea that seemingly unrelated impairments in a remote anatomical area can contribute to a primary complaint [2]—is key to understanding why an athlete with an old ankle injury or mobility restriction might quietly load their opposite hamstring toward failure.

Top Risk Factors for Hamstring Injury

Ankle Dorsiflexion and Running Mechanics:

Are Opposite-Side Injuries Linked?

I explored this concept in an article for Breaking Muscle, after working with a sprinter who returned to me with familiar right hamstring pain, months after surgery. He’d also suffered a prior right ankle fracture-dislocation, which left him with reduced dorsiflexion. That limited ankle motion had quietly changed his mechanics:

• Delayed toe-off

• Increased leg travel under the body

• Forward pelvic collapse

• Increased tension through the contralateral hamstring [3]

In other words:

Asymmetry and Lumbopelvic Control

👉 A stiff left ankle → forward-rotating pelvis → higher tensile load on the right hamstring

It wasn’t his hamstring strength holding him back—it was the unresolved movement pattern further down the chain.

“A forward rotating pelvis is a training error that increases tension on the right hamstring if it’s the left foot that collapses.” [3]

This is regional interdependence in action. It’s why hamstring injuries aren’t just hamstring problems. The British Journal of Sports Medicine do note the role of ankle dorsiflexion as a risk factor also.

Hamstring Injury Risk Factors

⚠️ Intrinsic Risk Factors You Might Miss

When we evaluate hamstring injury risk—or clearance for return to play—we need to screen more than strength. Research and clinical evidence highlight key intrinsic risk factors [4–6]:

✅ Poor lumbopelvic control

✅ Reduced hip extension range

✅ Asymmetrical hamstring strength

✅ Trunk lean asymmetry

Asymmetrical ankle dorsiflexion

✅ Reduced ankle dorsiflexion (especially contralateral side) (Teyhan et al, 2020)

Y-Balance Test and Injury Prediction

✅ Movement pattern asymmetries on FMS, Y-Balance, or SFMA assessments

Each unchecked hamstring injury risk factor adds another layer of compensation or vulnerability into an athlete’s movement system.

How to Prevent Recurrence: Practical Steps

🔍 What To Do About It?

If we only test isolated hamstring strength, we risk missing the bigger picture. Instead:

1. Screen pain, mobility, and asymmetry at the ankle, foot, hip, and pelvis.

2. Treat pain and restore mobility before adding load.

3. Develop competency at the ankle and foot—stability and motor control—before building capacity.

4. Use movement competency assessments (FMS, SFMA, Y-Balance) as part of clearance, not just isokinetic strength. You can get screened by me by booking a time here. You can also learn all about how to administer the FMS here.

“If you ignore quality to get quantity, you’ll get neither.” – Gray Cook [3]

🗣️ Final Thoughts

When 1 in 5 athletes re-injure their hamstring [2], we must ask: are we treating the site of pain, or the system that creates it?

Have you seen opposite-side or regional interdependence patterns in your athletes? How do you integrate whole-body screening into hamstring rehab and prevention?

The FMS Level 1 Course

I’d love to hear your strategies in the comments below. And for a deeper dive into AFL hamstring injury rehab, read my article here.

References

1. AFL.com.au. Alastair Clarkson unleashes in wake of North Melbourne Kangaroos Paul Curtis lengthy ban. Link.

2. Dea, G. AFL hamstring injury rehab: A framework for returning-to-play an AFL footballer from a grade 1 hamstring strain (extended version) Link

3. Dea, G. How Fixing Your Ankles Will Safeguard Your Hamstrings. Breaking Muscle. Link.

4. Warren P, et al. Clinical predictors of time to return to competition and of recurrence following hamstring strain in elite Australian footballers. Br J Sports Med, 2010.

5. Gabbe BJ, et al. Predictors of hamstring injury at the elite level of Australian football. Scand J Med Sci Sports, 2006.

6. Fousekis K, et al. Intrinsic risk factors of non-contact quadriceps and hamstring strains in soccer: a prospective study of 100 professional players. Br J Sports Med, 2011.