Myth #14 - Morning and Evening Workouts Build Similar Muscle

The claim: one workout time is uniquely best for muscle and performance.

A 2019 systematic review and meta-analysis of 11 studies found similar long-term strength and muscle-size gains from morning and evening resistance training. Evening strength can be higher in a single session, which does not establish greater muscle growth over time. 1

In a 20-week MRI study, quadriceps size increased 2.7% with morning training and 3.5% with afternoon training. The 0.8-point difference was not statistically significant. 2 A 2023 systematic review found no clear overall winner. Matching training and testing times may help when you compare same-time performance, while many included studies had a high risk of bias. 3

The swap: choose an hour you can protect, train at that time consistently, track your lifts, and test at the same time when comparisons matter.