Neural jitter and grip signal quality

Can a simple one-second squeeze predict your risk of cardiovascular disease, cognitive decline, and all-cause mortality? Dr. Jordan Feigenbaum and Dr. Austin Baraki explore why grip strength has become the go-to metric for the longevity industry and why most people are interpreting the data incorrectly.

Timestamps:

• [00:00] Intro: The Longevity Industry’s Thermometer Error
• [01:42] The Neuro-Axis: Anatomy of a Maximal Squeeze
• [06:43] The 35-3-5 Rule: Biomechanics of Grip
• [09:12] Asymmetries and Clinical Red Flags
• [17:31] Dynapenia vs. Sarcopenia: Why the Hand Fails First
• [18:41] Normative Data and the PURE Study Statistics
• [27:16] Genetics, Lean Body Mass, and Predictive Power
• [31:44] Absolute vs. Relative Grip Strength (The Metabolic Signal)
• [37:03] Bro-Science Beatdown: Neural Jitter and Training Readiness
• [42:19] The Extensor Training and "Grip Maxing" Myth
• [45:13] Programming: Systemic Training vs. Indirect Grip Work
• [48:10] The Straps Debate: Are You Killing Your Gains?
• [52:03] Final Verdict: Hierarchy and Health Priorities

Key Takeaways:

• Grip is Systemic: Handgrip strength tests the integrity of the entire system, from the motor cortex in the brain down to the tendons and bones. It is a proxy for overall muscular quality and neurological health.
• Predictive Power: According to the PURE study, for every 5 kg decrease in grip strength, there is a 17% increased risk of cardiovascular death and a 7% increased risk of non-cardiovascular death.
• The Sarcopenia Floor: Clinical "red zones" for probable sarcopenia are <27 kg for men and <16 kg for women.
• Relative Strength Matters: Relative grip strength (Grip Strength ÷ BMI) is a more accurate predictor of hypertension, diabetes, and dyslipidemia than absolute grip strength alone.
• Don't Chase the Test: Direct grip training (crushers, etc.) obscures the predictive power of the test. To improve health, focus on indirect systemic resistance training (training the whole body) rather than "gaming" the thermometer.

Next Steps

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