Fascicle Cross-Section & Motor Unit Recruitment
FAST-TWITCH TYPE-II
38.5% Atrophy
INTRAMUSCULAR FAT
14.2% Infiltration
ACTIVE MOTOR UNITS
74 / 100 Units
Lifespan & Intervention Workbench
65 years
30 yrs (Peak)
60 yrs
90 yrs (Advanced)
0 days / week
Sedentary (0d)
Moderate (2-3d)
Athlete (5d)
3 weeks
None (0w)
3 Weeks (Acute)
12 Weeks (Severe)
0.80 g / kg / day
0.6 (Low)
1.2 (Optimal Senior)
2.0 (High)
MUSCLE MASS RETENTION
74.2%
vs. Peak 30-yr baseline (100%)
GRIP STRENGTH FORCE
22.4 kg
Cutoff threshold: < 27 kg (Men)
5x SIT-TO-STAND TIME
14.8 sec
Sluggish cutoff: > 15.0 sec
EWGSOP2 RISK DIAGNOSTIC
Moderate Risk
Probable sarcopenia based on muscle mass retention and functional speed.
Ref: EWGSOP2 Consensus Criteria
Evidence-Based Preventative Protocol Roadmap
1. Progressive Resistance Stimulus
Fast-twitch Type-II motor units atrophy preferentially without high-threshold mechanical load. Engage in compound multi-joint resistance training 2–3x weekly.
2. Anabolic Protein Threshold
Aging muscle exhibits anabolic resistance. Consume 1.2–1.6g protein per kg/day with 3g Leucine per meal to trigger maximal muscle protein synthesis (MPS).
3. Rapid Disuse Countermeasures
A single 10-day period of bedrest or illness can cause up to 1kg of lean leg mass loss in older adults. Initiate early active mobility protocols immediately post-injury.