Mechanical tension
Mechanical tension is the force a muscle fibre bears while contracting against resistance, and it is the primary stimulus for hypertrophy. It is produced either by a heavy load or by taking a moderate-load set close to failure, because on the last reps the nervous system recruits the higher-threshold fibres and those work at low velocity.
Mechanical tension is the force a muscle fibre bears while contracting against resistance, and it is the primary stimulus for hypertrophy. It is produced either by a heavy load or by taking a moderate-load set close to failure, because on the last reps the nervous system recruits the higher-threshold fibres and those work at low velocity.
In practice
It explains why a set of 20 taken to the limit and a heavy set of 5 produce similar adaptations: both end with the same fibres working at low velocity. The difference is in the cost, not in the stimulus.
The common mistake
Treating it as a synonym for the weight on the bar. A heavy set stopped five reps short of failure produces less effective tension than a light one taken to the limit, whatever the number on the plate says.
