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 Interested in learning more about the Universal Speed Rating? Click here [https://universalspeedrating.com/lear...] to schedule a quick call with our team.