Blog
30-second chair stand test score chart: norms by age and protocol
Use the 30-second chair stand test score chart, protocol, and age norms to measure leg strength, fall risk, and progress safely at home without equipment.
Apple Health mobility metrics: complete guide to walking data
Apple Health mobility metrics explained: walking speed, step length, asymmetry, double support time, steadiness, stair speed, and trend changes.
Apple Watch gait metrics explained: walking asymmetry, steadiness, and double support time
Understand every Apple Watch and iPhone gait metric including walking asymmetry, steadiness, double support time, and step length. Learn what normal values mean.
Double support time by age: normal ranges chart and what high values mean
See double support time by age with practical normal ranges, Apple Health context, trend interpretation and signs worth discussing with a clinician.
Fitness benchmarks by age: how strong, fast, and fit should you be
Age-based fitness benchmarks for cardio, strength, balance, mobility, and body composition. Learn what to test, what matters, and how to track progress.
7 functional fitness tests linked to longevity risk
Seven home-friendly functional fitness tests linked with longevity research: grip strength, balance, gait speed, sit-to-stand, push-ups, VO2 max, and more.
Grip strength test at home: how to measure and what your score means
Learn how to test your grip strength at home with or without a dynamometer. Includes normal values by age and gender, scoring chart, and exercises to improve.
Muscle mass by age: how much you lose per decade and how to stop it
See how much muscle mass you lose per decade after 30 with charts by age and gender. Learn the science of sarcopenia and proven strategies to preserve muscle.
VO2 max by age and gender: chart, norms, and what's a good score
Complete VO2 max chart with normal values by age and gender. Find out where you rank, what a good score looks like, and how Apple Watch estimates your VO2 max.