Single-Leg Training, Eccentric Strength, and Why the Quadriceps Matter More Than You Think

Single Leg Training for Hockey

If there’s one training method that continues to be undervalued in sport performance, it’s unilateral work. Not because bilateral lifts aren’t useful — they are — but because sport is rarely bilateral. Skating, sprinting, cutting, jumping, and even swimming propulsion all occur one limb at a time.

And when you look at the research on quadriceps activation across exercises and depths, the case for single-leg, deep, and controlled eccentric training becomes even stronger.

Let’s reframe this conversation using what we now understand about quadriceps activation, eccentric loading, and performance demands.

Quadriceps Activation Increases With Depth

EMG research consistently shows that quadriceps demand increases as knee flexion increases. Partial squats produce less activation than parallel squats, and deep squats produce the highest quadriceps loading.

The key takeaway?

Quadriceps loading is not just about external weight. It’s about knee flexion.

Clinically, this matters. Athletically, it matters even more.

• Deeper knee angles increase quad demand.

• Unilateral tasks often match or exceed bilateral loading.

• Depth tolerance becomes a trainable quality.

If an athlete cannot control 80–90 degrees of knee flexion eccentrically on one leg, they are not prepared for the demands of sprinting or skating — regardless of their back squat numbers.

Why Eccentric Quadriceps Strength Is the Foundation

Most sport movements are not concentric first. They are eccentric first.

Every stride in skating or sprinting begins with force absorption:

• You contact the ground (or ice).

• You decelerate.

• You control knee flexion.

• Then you re-accelerate.

That deceleration phase is eccentric quadriceps strength.

Without it:

• Knee valgus increases.

• Patellofemoral stress increases.

• Ground contact time increases.

• Force production decreases.

Research on vastus medialis activation shows that deeper, controlled, and eccentric-focused tasks (wall sits 60–90°, Spanish squats, slow step-downs, split squats) drive higher activation.

That means eccentric control isn’t just about strength — it’s about coordination and joint control under load.

In rehab, this is injury prevention.

In performance, this is acceleration.

The Role of Each Quadriceps Muscle

Understanding how each component behaves changes how we train.

Vastus Medialis

Activation improves with:

• Depth

• Control

• Eccentric loading

This muscle is critical for patellar tracking and frontal plane knee stability. Inadequate eccentric control here is a common contributor to anterior knee pain.

Vastus Lateralis

Often the dominant quadriceps muscle in closed-chain tasks.

Highly active in:

• Hack squats

• Knee extensions

• Back squats

• Leg press (low foot position)

It generates force effectively but does not replace the need for medial stability.

Rectus Femoris

Contributes less during deep squats due to its biarticular role (hip and knee).

More active during:

• Knee extension

• Straight leg raise

• High step-ups

• High cadence cycling

This explains why deep squats alone are not enough for complete anterior thigh development — especially in athletes who rely heavily on hip flexion velocity (like hockey players).

Injury Prevention vs. Performance: False Dichotomy

Too often, we separate “injury prevention” from “performance.”

But eccentric quadriceps strength lives at the intersection of both.

Injury Prevention Role:

• Controls knee valgus under load

• Improves patellar tracking

• Reduces patellofemoral joint stress

• Enhances tendon resilience

• Builds tolerance to deep knee flexion

Athletes with poor eccentric control don’t just underperform — they compensate. And compensation is where overuse injuries live.

Performance Role:

• Shortens ground contact time

• Improves stride frequency

• Enhances force per foot contact

• Increases acceleration capacity

• Improves repeated sprint endurance

Newton’s second law still applies: acceleration is proportional to force.

But in sport, force must be generated in fractions of a second — often less than 0.2 seconds per contact.

You cannot produce force quickly if you cannot absorb it first.

Eccentric control is the gateway to concentric power.

Why Single-Leg Training Still Wins

Single-leg training:

• Matches sport mechanics.

• Increases quadriceps activation.

• Challenges frontal plane control.

• Improves hip–knee–ankle coordination.

• Exposes asymmetries bilateral lifts hide.

A bodyweight single-leg squat represents roughly 70%+ of body mass in effective loading. Add depth and tempo control, and the demand escalates quickly.

The old rule still applies:

If you cannot control 90° of knee flexion for six clean reps, you have not earned the right to add more load.

But here’s the modern upgrade:

If you cannot control 90° eccentrically with tempo on one leg, you are not prepared for sport speed.

Application to Hockey (and Any Speed Sport)

Elite hockey players skate at knee angles roughly between 75–85 degrees during shifts that last 40+ seconds.

That means:

• Repeated deep knee flexion.

• Repeated eccentric absorption.

• Repeated rapid force production.

Your hockey coach does not care about your 1RM squat.

They care about:

• Acceleration.

• Top-end speed.

• Shift repeatability.

• Durability over a season.

Stride frequency improves when:

• Hip flexors are explosive.

• Ground contact time decreases.

Ground contact time decreases when:

• Eccentric control is efficient.

• Force transfer is clean.

• The knee doesn’t collapse under load.

The more distance you achieve per stride, the faster you accelerate.

The more efficiently you can repeat it, the more dominant you become.

Practical Programming Principles

If your goal is both durability and dominance:

1. Train deep knee flexion progressively.

2. Emphasize slow eccentric phases (3–4 seconds down).

3. Use unilateral patterns early in training blocks.

4. Include isometric holds at 60–90° for tendon capacity.

5. Progress toward speed-strength once eccentric control is earned.

Example hierarchy:

• Wall sits (60–90°)

• Spanish squats

• Slow step-downs

• Split squats

• Rear-foot elevated split squats

• Single-leg squats

• High box step-ups

• Loaded unilateral jump variations

Eccentric control → Strength → Speed → Repeatability.

Single-leg training is not just a method.

It is a bridge.

A bridge between rehab and performance.

Between strength and speed.

Between surviving a season and dominating one.

Speed intimidates.

Speed wins.

But speed is built on eccentric strength.

The question isn’t whether you should train single-leg.

The question is whether you’re ready to train like your sport actually demands.