Nordic Curls vs Easy Curls Protect Against Injury Prevention

Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before making health decisions.

Understanding Nordic Curls

Two brothers were tragically shot and killed in New Orleans, highlighting how a lack of precaution can have dire consequences. Nordic curls and easy curls both strengthen the hamstrings, reducing injury risk, yet Nordic curls provide greater eccentric load for advanced athletes while easy curls offer a gentler introduction for beginners.

In my experience coaching runners, I see Nordic curls as the "big brother" of hamstring work. They involve anchoring the heels and lowering the torso using only the hamstrings, creating a high-tension eccentric contraction. This movement mimics the deceleration phase of sprinting, where the hamstrings act as brakes. Because the load is body-weight plus any added resistance, the exercise challenges both strength and neuromuscular control.

When I first introduced Nordic curls to a seasoned middle-distance athlete, his initial wobble turned into a solid, controlled descent after just three sessions. The key is progression: start with a limited range, perhaps only lowering halfway, then gradually increase the depth as confidence grows. The eccentric emphasis improves muscle fiber recruitment, especially the type II fibers most vulnerable to strain during high-speed running.

Research on eccentric hamstring training shows a reduction in strain-type injuries by up to 50% when performed consistently over eight weeks. While the exact figure varies across studies, the trend is clear: eccentric overload builds resilience. For beginners, however, the steep learning curve can lead to form breakdown and lower-back fatigue, which is why easy curls serve as a stepping stone.

Key Takeaways

• Nordic curls deliver high eccentric load for advanced athletes.
• Easy curls provide a safer entry point for beginners.
• Both exercises target hamstring strength and injury prevention.
• Progressive depth is essential for proper Nordic curl form.
• Consistent eccentric training can cut hamstring strain risk.

What Are Easy Curls?

Easy curls, sometimes called assisted Nordic curls or prone hamstring curls on a stability ball, reduce the load by allowing the feet to remain on the ground or by using a partner for support. In my own training sessions, I start clients on a stability ball, where they curl the hips upward while the ball provides a pivot point for the ankles. This variation isolates the hamstrings without demanding the full body-weight resistance of a true Nordic curl.

The movement pattern is similar: the hips extend while the knees stay relatively stable, but the ankle joint does not bear the entire load. This adjustment means the lower back stays more neutral, decreasing the risk of lumbar strain. For novice runners, easy curls build the foundational neuromuscular pattern needed before tackling the full Nordic version.

From a biomechanical standpoint, easy curls generate approximately 30-40% less peak force compared to traditional Nordic curls. That reduction makes the exercise more forgiving while still delivering sufficient stimulus to stimulate hypertrophy and improve tendon stiffness. Over time, as the athlete’s hamstrings adapt, the load can be incrementally increased by reducing assistance or adding ankle weights.

In my program design, I schedule easy curls two times per week for beginners, focusing on 3 sets of 8-10 reps with a controlled tempo (2 seconds down, 2 seconds up). This cadence ensures time under tension, a critical factor for muscle remodeling. As the runner progresses, I transition them to the full Nordic curl, preserving the hard-earned strength gains.

Biomechanical Comparison

When choosing between Nordic curls and easy curls, it helps to look at the numbers side by side. The table below breaks down key variables that affect injury-prevention potential for runners.

*Scores are based on consensus from physiotherapy literature and practitioner experience. The higher eccentric load of the Nordic curl translates to greater adaptation in the hamstring musculotendinous unit, which is why it scores higher for athletes who can execute it safely.

Nevertheless, the easy curl’s lower technical barrier makes it a valuable tool in the early phases of training. My recommendation follows a “graduated overload” philosophy: start with easy curls to build movement literacy, then progress to Nordic curls for maximal protective benefit.

Injury Prevention Evidence

When I look at the data from sports medicine clinics, the pattern is consistent: athletes who incorporate eccentric hamstring work experience fewer strains. A 2021 review of elite sprinters found that those who performed Nordic curls twice weekly reduced hamstring injury incidence by roughly half compared with a control group. Although the exact numbers vary, the consensus supports eccentric training as a cornerstone of injury-prevention protocols.

For beginners, the evidence is more nuanced. A study published in the Journal of Strength and Conditioning Research examined novice runners who added easy curls to a 12-week program. Results showed a 30% improvement in hamstring flexibility and a modest reduction in reported soreness, suggesting that even low-load eccentric work can confer protective benefits.

From a physiotherapy perspective, the hamstring’s two-joint nature makes it vulnerable during high-speed running. The biceps femoris, in particular, undergoes rapid lengthening in the late swing phase, a situation ripe for strain. By strengthening the muscle eccentrically, we improve its ability to absorb force, effectively acting as a biological brake.

My clients often ask whether they should add Nordic curls right away. The answer depends on their current strength, core stability, and injury history. Those with a solid foundation in squats, deadlifts, and core work can usually tolerate the higher load, while newcomers benefit from the assisted variation until they demonstrate proper form.

Programming for Runners

Integrating hamstring work into a running program requires balance. Overloading the posterior chain can spill over into the lower back, so I follow a periodized approach. In the base-building phase (weeks 1-4), I prescribe easy curls twice weekly, focusing on controlled tempo and moderate volume.

As the athlete approaches the specific-training phase (weeks 5-8), I introduce Nordic curls with a reduced range - perhaps only lowering to a 45-degree angle. This incremental load respects the principle of progressive overload while preserving running mileage.

During peak race preparation (weeks 9-12), the goal shifts to maintaining strength. I keep Nordic curls in the program but drop the volume to 2 sets of 5 reps, ensuring the hamstrings stay primed without causing excessive fatigue.

Here is a sample weekly layout for a 10-k runner:

1. Monday: Easy curls 3 × 10, core circuit.
2. Wednesday: Tempo run + mobility drills.
3. Friday: Nordic curls 2 × 6 (partial depth), glute bridges.
4. Saturday: Long run, focus on stride mechanics.

Notice the spacing of strength sessions to allow recovery between hard runs. This sequencing aligns with the principle that muscular adaptations occur during rest, not during the workout itself.

For trail runners who encounter uneven terrain, I also add single-leg Nordic variations on a stable platform to improve unilateral stability. The added challenge translates to better ankle-knee coordination on technical sections, further reducing the chance of a sudden hamstring pull.

Practical Tips for Safe Execution

Whether you are a seasoned marathoner or a beginner jogger, safety starts with preparation. Below are my go-to cues that keep the lower back neutral and the hamstrings doing the work.

• Anchor securely: Use a sturdy bar, partner’s hands, or a resistance band to hold the heels.
• Engage the core: Draw the belly button toward the spine to prevent lumbar hyperextension.
• Control the descent: Aim for a 3-second eccentric phase; speed often compromises form.
• Maintain a slight knee bend: This reduces shear forces on the joint and focuses tension on the hamstrings.
• Progress depth gradually: Start with a 30-degree angle, then add 10 degrees each week as confidence builds.

In my clinic, I use a simple visual cue: imagine the torso as a pendulum swinging down from the hips, not a forward roll. This mental image helps athletes keep the shoulders relaxed and the hips leading the movement.

If you feel low-back strain, drop back to easy curls or place a foam roller under the hips to limit hip flexion. Listening to your body is paramount; pain beyond normal muscular fatigue signals that the load is too high.

Finally, remember that consistency beats intensity for injury prevention. A few well-executed reps each week are more valuable than occasional heavy sessions that jeopardize technique.

Frequently Asked Questions

Q: Can beginners safely perform Nordic curls?

A: Beginners should start with assisted variations such as easy curls or partial-range Nordic curls. Building core stability and hamstring awareness first reduces the risk of lower-back strain and ensures proper technique before progressing to full-body-weight loads.

Q: How often should runners incorporate hamstring curls?

A: For most runners, two sessions per week - one easy curl and one Nordic curl - provide enough stimulus without compromising mileage. Adjust frequency based on training phase and individual recovery capacity.

Q: Do Nordic curls replace traditional hamstring exercises?

A: Nordic curls are an excellent eccentric complement but should not wholly replace compound movements like deadlifts or lunges. A balanced program mixes both to develop strength, power, and functional movement patterns.

Q: What signs indicate I’m over-doing hamstring work?

A: Persistent soreness, sharp low-back pain, or a loss of range of motion are red flags. Reduce volume, focus on mobility, and consider swapping to easy curls until the discomfort subsides.

Q: How do I track progress with these curls?

A: Record the depth achieved, number of reps, and any added weight. Over weeks, improvements in depth and rep quality signal increased hamstring resilience, which correlates with lower injury risk.