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Calf muscle abilities are related to sprint performance in male Rugby Union players

Hébert-Losier, K., Balsalobre-Fernandez, C. and O'Neill, S., 2023. Calf muscle abilities are related to sprint performance in male Rugby Union players. Physical Therapy in Sport, 64, pp.117-122.

In today’s letter

• Overview of whether calf muscle strength & endurance correlate with overall athletes sprint performance

• A fun infographic for you to save and use in the future

• Rapid Results =

The study found a strong correlation between calf muscle performance (power and strength-endurance) and 10-meter sprint times in Rugby Union players. Specifically, higher metrics for weighted power, total work, and total displacement were closely linked with faster sprint acceleration

• 3 resources to check out to further your knowledge about the calf complex

• Meme of the week: Oh um, haha

Aim of the study

The study aims to look into the relationship between calf muscle performance—specifically power and strength-endurance metrics—and 10-meter sprint times in Rugby Union players.

It seeks to provide information for improving rehabilitation, injury prevention, and athletic performance.

Calf Muscles & Acceleration

When it comes to speed and acceleration, most people think about the main movers like the hamstrings, glutes, and quads.

And thats not wrong, the big boys do contribute heavily

But the the calf complex (gastrocnemius, soleus, and Achilles tendon) is underlooked and undervalued too often. These muscles/structures are majorly involved in explosive movements, and research consistently shows their direct impact on short-distance sprints, especially over 10 meters.

During acceleration, the calf muscles and Achilles tendon produce forces as high as 16 times body weight.

That’s an enormous workload for a relatively small group of muscles. In sports like Rugby Union, where short bursts of speed are critical for breaking tackles or scoring tries, the ability to generate quick power is fundamental.

The study highlights that higher calf power (measured with bodyweight and weighted tests) and strong endurance directly correlate with faster sprints.

For physiotherapists and S&C coaches,

This is a reminder to think (somewhat) out of the box and start prioritising the calf muscles in both rehab and performance plans.

While the larger muscle groups often steal the attention, the calves are essential for powering those first few steps of acceleration.

In addition,

Helping your athletes understand how important this muscle group is can make a big difference. When they know how improving their calf strength and endurance will help them sprint faster or move more explosively, they’ll be more motivated to stick to their programs.

Strong Calves = Injury Prevention

Working on the calf complex isn’t just for performance — it’s also important when we want to keep our patients and athletes injury-free.

Given how much strain the gastro & soleus muscles endure during training and competition, it’s no surprise that calf and Achilles injuries are among the most common in sports like Rugby and football. In fact, they’re second only to hamstring injuries.

One key factor here is fatigue.

As the calf muscles tire, their ability to generate force and stabilise the ankle decreases. This not only slows an athlete down but also raises the risk of injuries, particularly in high-impact movements like cutting, or landing.

For physios, this means keeping a close eye on calf muscle function and addressing any weaknesses before they become a problem.

The study points out that looking at total work—a combination of force, movement, and efficiency—is a better way to evaluate calf endurance than just counting reps. Tests like the weighted power test can help identify issues without putting unnecessary strain on the athlete.

Adding simple prehab exercises like eccentric calf raises and ankle stability work into training programs can also help prevent injuries.

Keeping the calf complex strong and resilient is one of the best ways to ensure your athletes stay on the field and perform at their peak.

Clinical Tip

Use the weighted power test when assessing calfs to measure an athlete’s calf muscle power and its impact on sprint acceleration.

This test is quick, easy to perform, and less likely to cause soreness, making it ideal for tracking performance or determining readiness for return-to-play.

Setup:

1. Equipment: Raised box, 35 kg dumbbell, towel (for shoulder comfort), wall for balance.

2. Position:

   • Athlete stands with forefoot on the edge of the box, heel hanging off.

   • Test leg remains straight; non-tested leg is lifted behind.

   • Dumbbell rests on the ipsilateral shoulder, supported by a towel.

   • Fingertips (up to five) touch the wall for balance.

Execution:

1. Athlete starts with both heels lifted high.

2. Perform three repetitions of lowering the test heel (eccentric) and quickly raising it (concentric) to maximum height.

3. Rest for 2 seconds between reps and 30 seconds before switching legs.

Data Collection:

1. Record peak power (W) during the concentric phase for each rep. (using The Calf Raise application)

2. Use the highest value for each leg.

3. Average the results of both legs for analysis.

Top 3 Resources to Check Out

And learn more about…

1. Phases of rehab after injury - Practical guidelines (PDF) - LINK 🏉

2. Everything you need to know about calf strains (article by yours truly) - LINK 👨‍⚕️

3. Great Lecture from Aspetars clinic 🎥

Meme of The Week

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

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