Lengthened partials, a weight-training technique that keeps each repetition in the half of the movement where the muscle is stretched, are used to build muscle for healthy aging. They appear to build muscle about as well as full-movement training, a sound alternative rather than a clearly superior one. Strength may lag where the muscle is short, and unfamiliar stretched-position work brings early soreness. Effects in older adults remain unknown. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Muscle thickness (ultrasound) or cross-sectional area (MRI) | No established target; track change from the individual's own baseline | Expected to change: growth |
| Strength at full range and at stretched and contracted angles (1RM, repetition maximum or static strength) | No established target; track change from the individual's own baseline | Expected to change; reveals contracted-range shortfall |
| Creatine kinase (CK) | About 20–200 U/L, laboratory-dependent | Safety check: very high values with symptoms stop training |
Cadence: Baseline before starting; muscle size and strength every 8–12 weeks (size at least 72 hours after the last session); training logs weekly; resting CK at baseline for statin users or those with prior muscle injury, rechecked only if unusual symptoms appear, such as dark urine, severe swelling or weakness lasting several days