Using Performance Testing and Specific Strength & Conditioning to improve your CMJ

The countermovement jump (CMJ) is a reliable indicator of performance potential in sports ranging from basketball and volleyball to rugby and sprinting. Athletes approach the CMJ differently—some rely heavily on muscular input, while others utilise tendon elasticity.

Understanding your jump style helps you optimise your training in the gym and tailor your strength & conditioning strategy for maximum performance gains.

At Performance Dynamics gym, we identify our athletes’ CMJ style based on three elements: countermovement depth, contraction time, and a visual inspection. Combined these tell us whether they are a muscular-driven or a tendon-driven jumper.

In this post we’ll be looking at Hao, a muscular-driven jumper who achieved an amazing 61.4cm in testing.

How He Did It

First, it’s important to understand the athlete. Hao is an ex-sprinter with a personal best of under 11 seconds over 100 metres (he’s quick!).

Hao also has some impressive lifting numbers, with a 2x bodyweight back squat and a 1.5x bodyweight clean (he’s a well-developed athlete!).

We would expect Hao’s CMJ to look like this:

• A deeper squat to lengthen the muscles and give him time to develop tension.
• A contraction time of more than 650ms (how long it takes to get down and back up).
• It will look like the loading part of the movement lasts longer than the explosive part.

 

 

Let’s analyse the advanced biomechanical strategy Hao used for his super CMJ.

1. Unweighting and Heel Lift

As Hao initiates his countermovement, you’ll notice his heels slightly lift from the floor. This subtle heel lift isn’t a mistake—it’s an effective “unweighting” strategy, allowing him to transition quickly into a deeper eccentric squat without excessive force.

2. Deep Squat and Contraction Time

Hao’s squat depth is notably deep (just over 52cm), and his contraction time is notably long (800ms). These traits are typical of muscular-driven jumpers who need more time to build muscular tension.  

3. Forward Foot Roll and Stretch Shortening Cycle at the Ankle

At the lowest point of the squat, he distinctly rolls forward onto the balls of his feet. Not to be confused with the heal lift during unweighting, this is for a different and important reason.

Why is this important?

• This forward shift causes foot supination, forming a strong and stable arch.
• It lengthens the Achilles tendon, creating significant stiffness and tension through the calf-Achilles complex, visibly increasing muscle tone in his calves and setting him up for SSC contribution from the Achilles tendons.
• The foot supination pairs with external rotation at the hips, creating space for internal hip rotation during the concentric phase, generating substantial torque and power through the hips.

 

 

4. Stretch-Shortening Cycle at the Knee

As he turns over in the bottom we see a further forward shift onto the balls of the feet, this one lengthens the patellar tendon, initiating an additional stretch-shortening cycle (SSC) around the knee. This extra SSC contributes valuable elastic recoil just before Hao pushes upward.

4. Concentric Drive and Powerful Acceleration

As Hao transitions upward, there’s a clear increase in speed, highlighting his exceptional ability to generate muscular force rapidly. Approaching take-off, his knees aggressively snap back just before leaving the ground, indicating significant quadriceps engagement for the final push. The explosive force produced creates a visible “pop” as he leaves the ground, sending a wave-like energy transfer through his legs as he moves into the air.

This coordinated muscular-driven technique enables Hao to effectively convert deep eccentric loading into an impressive vertical jump of 61.4cm.

Applying These Insights to Your Strength & Conditioning Programme

Identifying whether you’re muscular-driven or tendon-driven in your CMJ allows for more precise and effective strength & conditioning planning in the gym.

For Muscular-Driven Athletes we recommend

• Prioritising strength training with heavier loads and slower, controlled eccentric phases to enhance muscular tension and power production.
• Incorporating exercises such as deep back squats, front squats, and heavy deadlifts to build robust lower-body strength.
• Using drills that include pauses or slower eccentric movements, helping develop force under tension more effectively.

How Performance Dynamics Can Help

At Performance Dynamics gym, our coaches use advanced performance testing methods to determine your unique jump profile, allowing us to build personalised programmes that match your biomechanics. Tailored coaching ensures each athlete receives targeted guidance, enhancing overall athletic performance and reducing injury risk.

Next Steps: Personalised Training for Athletes

Ready to optimise your jump performance and overall athletic potential? At Performance Dynamics gym, we specialise in personalised assessments and tailored strength & conditioning programmes. Through personalised coaching and biomechanical insights, we’ll help you build greater athleticism, power, and resilience tailored precisely to your unique profile.

If you’re committed to enhancing your athleticism through expert coaching and targeted training strategies, apply HERE to begin your journey.