Stretch Shortening Cycle & The Role Of Pre-Tension

In this solo episode of The Speed Lab Podcast, Les Spellman breaks down one of the most misunderstood aspects of sprinting: the stretch shortening cycle (SSC) and the critical role of pre-tension. Drawing from research, coaching experience, and case studies, Les explains why faster sprinters actually produce higher braking forces, how tendons act as both shocks and springs, and why athlete development often overlooks eccentric qualities. 

Episode Timestamps

• 00:00 – Intro & why this topic matters
• 01:15 – Braking forces & the stretch shortening cycle explained
• 05:00 – Early coaching mistakes & concentric-only bias
• 08:00 – Why concentric strength doesn’t separate elite sprinters
• 10:15 – Hypothesis: performance = pretension + braking + transition + propulsion
• 11:00 – Tendons as shock absorbers & springs
• 13:30 – Force plates as a window into SSC
• 17:00 – Case study: Jacob Robinson’s eccentric RFD breakthrough
• 21:00 – Case study: River Cracraft tendon remodeling
• 23:30 – Case study: Brandon Jetter improving pretension & ground contact
• 28:45 – Pretension mechanics & dribble drills
• 31:00 – Practical takeaways from force plate metrics
• 35:15 – Training interventions: yielding/overcoming isometrics, reflexive eccentrics, plyos
• 38:45 – Programming ideas (slow, high, and fast force days)
• 42:00 – Redefining “stiffness” & SSC strategy
• 43:20 – Wrap-up, resources, and closing thoughts

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