Personalized Jump Training by Tendon Elasticity
Jump Training Programming Based on Tendon Elasticity: Toward Personalized Performance
INTRODUCTION
For years, strength and conditioning coaches have placed athletes into simple categories—strong or fast, powerful or enduring. But as flywheel training and eccentric movement strategies gain traction in elite sports, a new physiological variable is taking center stage: tendon stiffness. Thanks to foundational studies like Kubo et al. (1999), we now understand that traditional strength methods or basic concentric training may not deliver optimal results for everyone. By introducing flywheel resistance training especially with tools like flywheel squat machines or exxentric flywheels coaches can now tap into tendon elasticity as a key driver of explosive performance and individualized athletic progress.
This article bridges science and practice by offering concrete strategies for coaches looking to integrate tendon profiling into their jump training programs.
KEY CONCEPT: TENDON STIFFNESS AND THE SSC
The stretch-shortening cycle (SSC) is a natural mechanism in which an eccentric action followed by a rapid concentric action (like a countermovement jump) enhances force output via stored elastic energy. The tendon plays a central role here:
- Compliant tendon: more capable of elongation and elastic energy storage.
- Stiff tendon: less deformation, greater direct force transmission.
Kubo et al. showed that the difference between a countermovement jump (CMJ) and a squat jump (SJ) is inversely related to tendon stiffness. In short, athletes with more elastic tendons benefit more from the SSC.
STEP 1: IDENTIFY TENDON PROFILE
While ultrasound offers the most precise assessment, coaches can use more practical tools:
- Compare CMJ vs SJ: a difference >10% suggests good SSC use and compliant tendons. <5% may indicate stiffness or poor coordination.
- Load-displacement curve on a force plate (if available).
- Clinical observation: bouncier athletes with low ground contact times are typically more elastic.
STEP 2: CLASSIFY ATHLETES BY PROFILE
- Elastic Profile (Compliant)
- Efficient SSC use
- Large CMJ > SJ difference
- Responds well to plyometrics
- Stiff Profile
- Low SSC benefit
- Strong concentrically but less reactive
- Needs strength/RFD development and neuromuscular timing
STEP 3: PROGRAM DESIGN ACCORDING TO PROFILE
Component | Elastic Profile | Stiff Profile |
|---|---|---|
Primary Focus | Reactivity / High-velocity plyometrics | Max strength / Rate of force development |
Jump Type | Low-contact hops, pogos | CMJs with load, jump squats |
Strength Work | Light eccentrics / isometrics | Heavy trap bar DL, deep squats |
Progression | Gradual volume increase | Progressive intensity increase |
Weekly Frequency | 2–3 pure SSC sessions | 1–2 SSC + 2 strength sessions |
STEP 4: ADAPTATION OVER THE SEASON
Tendon stiffness is adaptable over time. A smart periodization strategy can enhance the structural and mechanical qualities of the tendon:
- Base phase: emphasize slow strength and isometrics
- Development phase: introduce low-intensity plyos (box jumps, linear hops)
- Pre-competition: target fast SSC, multidirectional, sport-specific drills
Example progression for a stiff-profile athlete:
- Deep squat isometrics (3 weeks)
- CMJs with moderate load + controlled eccentric drops (4 weeks)
- Drop jumps + quick-reactive hops (3 weeks)
CASE STUDY: FIELD APPLICATION
Imagine two athletes with the same 1RM in the squat but different jump behaviors:
- Athlete A: CMJ = 40 cm, SJ = 30 cm → 33% difference
- Athlete B: CMJ = 35 cm, SJ = 33 cm → 6% difference
Though equally strong, Athlete A benefits more from elastic recoil and should train with explosive plyometrics. Athlete B may need to develop SSC efficiency and possibly modify tendon stiffness to improve jump output.
FINAL COACHING GUIDELINES
- Test what matters: include CMJ vs SJ testing monthly.
- Train the missing link: some need more strength, others more reactivity.
- Think long term: tendon adaptations take time, but they’re trainable.
- Use science as your compass, not your GPS: profiles are guidelines, not absolutes.
CONCLUSION
Jump training rooted in tendon stiffness is redefining flywheel strength training as a pathway to personalized athletic development. By combining simple field assessments with advanced tools like flywheel training equipment, coaches can go beyond one-size-fits-all programs. Whether using inertia flywheels, eccentric flywheel devices, or flywheel exercise machines, understanding the behavior of connective tissue empowers trainers to deliver smarter, science-backed programming. It’s time to unlock performance with data, precision, and the power of flywheel fitness.
