Performance

The Science of Sweat: The Body's Cooling System

Sweating is a sophisticated cooling system that helped make humans extraordinary endurance travelers. Explore the science of sweat.

The Science of Recovery: Why Rest Days Make You Fitter

Training does not make you fitter—recovery does. Explore the science of recovery and why rest is an active part of getting stronger.

The Flow State: The Psychology of Total Absorption

In flow, action and awareness merge and time seems to vanish. Explore the psychology of the flow state and the conditions that make it possible.

Muscle Protein Synthesis: How Muscle Is Built and Lost

Muscle is in constant turnover, built up and broken down every day. Explore muscle protein synthesis and the balance that determines whether muscle grows.

VO2 Max: The Ceiling of Your Aerobic Engine

VO2 max measures the maximum rate at which your body can use oxygen. Explore what it represents and why it reflects the size of your aerobic engine.

Delayed Onset Muscle Soreness: What DOMS Really Is

The muscle soreness that peaks a day or two after exercise is widely misunderstood. Explore what DOMS really is—and what it is not.

Slow and Fast Twitch: The Two Kinds of Muscle Fiber

Your muscles contain different fiber types suited to different tasks. Explore slow-twitch and fast-twitch fibers and what they mean for performance.

Why Grip Strength Predicts More Than You Think

Grip strength is a simple measurement with a surprising reach. Explore why the strength of your hands serves as a window into whole-body health.

Progressive Overload: The Core Principle of Getting Stronger

Behind every effective training program lies one principle. Explore progressive overload and why the body only changes when it is asked to.

The Stretch-Shortening Cycle: The Spring in Every Jump

A muscle stretched just before it contracts produces more force. Explore the stretch-shortening cycle, the elastic mechanism behind every jump and stride.

Growth Hormone and Deep Sleep: The Nightly Repair Shift

The body's main release of growth hormone is tied to deep sleep. Explore the link between growth hormone and the nightly repair shift.

Heart Rate Variability: The Rhythm Beneath the Heartbeat

A healthy heart does not beat like a metronome. Explore heart rate variability and why the small variations between beats reveal so much.