The problem:
Garmin Connect currently estimates the training load of strength training sessions almost exclusively based on heart rate.
This is fundamentally inadequate for resistance training, because:
The cardiovascular system reflects neither local muscular effort nor nervous fatigue.
A heavy set of squats at RPE 9 might barely raise the heart rate, yet produce over 48 hours of neuromuscular fatigue.
Cardio-based load consistently underestimates the actual physiological cost of strength work.
The science:
Sports science research (Foster, Busso) has validated the session RPE (sRPE) method as the most reliable model for quantifying strength training load.
The formula is:
Load = RPE (1–10) × Time Under Tension (min) × Muscle Mass Coefficient
Where the Muscle Mass Coefficient accounts for the size of the muscle groups involved:
0.75 for isolation exercises (biceps, triceps, calves, shoulders)
1.00 for upper-body compound movements (chest, back, rows, presses)
1.50 for lower-body compound movements (squats, deadlifts, lunges)
Proposed feature:
Allow users to manually enter or edit the training load for strength training sessions in Garmin Connect, using the sRPE formula above.
This would make it it possible to:
Provide athletes with an accurate representation of strength training load Enable consistent integration with endurance training load metrics Align Garmin Connect with a methodology validated by sports science Benefit the growing number of hybrid athletes combining strength and endurance training
Reference:
The Intervals.icu platform already allows for the manual editing of load for strength training activities, and its users have developed custom formulas specifically for this purpose. Garmin Connect should offer at least the same level of flexibility.
