The Science

Weekly volume targets

What it means. Hard sets per muscle per week is the training variable most consistently linked to muscle growth. Each muscle gets a target range rather than a single number, because the useful dose is a band, not a point.

How we calculate it. We count your hard sets (warm-ups excluded) per muscle since your week start. A set counts 1.0 for a muscle the exercise trains directly and 0.5 when it's a supporting mover, so compound lifts credit the muscles they actually work. Large groups target roughly 10–20 sets per week, smaller ones less because they pick up substantial indirect volume from compounds.

Schoenfeld, B.J., Ogborn, D., & Krieger, J.W. (2017). Dose-response relationship between weekly resistance training volume and increases in muscle mass. Journal of Sports Sciences, 35(11).
Baz-Valle, E., et al. (2022). A systematic review of the effects of different resistance training volumes on muscle hypertrophy. Journal of Human Kinetics, 81.

Training monotony & strain

What it means. Monotony measures how similar your daily training loads are. Weeks where every day looks the same — no genuinely easy days — are associated with worse tolerance of the same total workload. Strain combines your total load with that sameness.

How we calculate it. Each day's load = hard sets × that day's average RPE. Over a rolling 7 days (rest days included as zero), monotony = mean daily load ÷ its standard deviation, and strain = weekly load × monotony. Monotony above roughly 2.0 alongside high strain is the pattern worth acting on. The fix is varying hard and easy days, not necessarily training less.

Foster, C. (1998). Monitoring training in athletes with reference to overtraining syndrome. Medicine & Science in Sports & Exercise, 30(7).
Foster, C., et al. (2001). A new approach to monitoring exercise training. Journal of Strength and Conditioning Research, 15(1).

Daily readiness

What it means. A single 0–100 read on how hard to push today, before you start. It is a planning aid, not a measurement of your body — it only knows what you've logged and what you've told it.

How we calculate it. Starts at 100 and subtracts for the things that predict a harder session: your own fatigue rating (1–9, which carries the most weight), training already done today or yesterday, consecutive training days, and how hard your last session's RPEs were. Your subjective rating dominates deliberately — self-reported wellness tracks readiness at least as well as objective markers.

Saw, A.E., Main, L.C., & Gastin, P.B. (2016). Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures. British Journal of Sports Medicine, 50(5).
Foster, C., et al. (2001). A new approach to monitoring exercise training. Journal of Strength and Conditioning Research, 15(1).

Estimated 1RM

What it means. An estimate of the most you could lift once, calculated from a set you actually performed. It lets you compare sessions fairly when reps and weight both change — 80kg×8 and 90kg×5 are hard to rank by eye.

How we calculate it. Epley's formula: weight × (1 + reps ÷ 30). We cap reps at 10 because the estimate inflates beyond that, so a high-rep set never fakes a personal record. For bodyweight movements your body weight plus any added load is used.

Epley, B. (1985). Poundage Chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises.
LeSuer, D.A., et al. (1997). The accuracy of prediction equations for estimating 1-RM performance in the bench press, squat, and deadlift. Journal of Strength and Conditioning Research, 11(4).

Next-session targets

What it means. What to lift next time for a given exercise. The app uses double progression: add reps at a fixed weight until you reach the top of the rep range, then add weight and start again at the bottom.

How we calculate it. We read your last three sessions of that exercise, using the heaviest work set from each (warm-ups and drop sets excluded). If you hit the top of the range at maximum effort, we raise the weight. If you're short of target at maximum effort, we hold. If the same weight has stalled for two sessions, we cut roughly 10% to rebuild. Otherwise we add a rep. RPE — reps in reserve — is what tells these cases apart, which is why rating a set matters.

Zourdos, M.C., et al. (2016). Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. Journal of Strength and Conditioning Research, 30(1).
Helms, E.R., et al. (2016). RPE and velocity relationships for the back squat, bench press, and deadlift in powerlifters. Journal of Strength and Conditioning Research, 31(2).

Muscle map & anatomical heads

What it means. Most trackers stop at "chest" or "legs". Muscles with several heads can be trained unevenly, and the map shows those heads separately so a gap doesn't hide inside a group that looks well covered overall.

How we calculate it. Each exercise is mapped to the heads it emphasises, with primary and supporting weights. Exercise selection genuinely shifts emphasis: seated calf raises bias the soleus while standing raises bias the gastrocnemius, because knee flexion slackens the two-joint gastrocnemius. Hip-hinge movements bias the medial hamstrings, knee-flexion movements the biceps femoris, and deep squats load the vasti more than open-chain extensions.

Kinoshita, M., et al. (2023). Effects of knee joint angle on triceps surae muscle hypertrophy after calf-raise training. Frontiers in Physiology, 14.
Maeo, S., et al. (2021). Greater hamstrings muscle hypertrophy but similar damage protection after training at long versus short muscle lengths. Medicine & Science in Sports & Exercise, 53(4).
Schoenfeld, B.J., et al. (2015). Regional differences in muscle activation during hamstrings exercise. Journal of Strength and Conditioning Research, 29(1).

Push / pull & quad / hamstring balance

What it means. The ratio of opposing movement patterns in your training. Persistent imbalance between agonist and antagonist work is commonly flagged in injury-risk screening — this is a training-distribution check, not a clinical assessment.

How we calculate it. We compare hard sets of pushing versus pulling work, and quad-dominant versus hamstring-dominant work, over your recent training. Roughly balanced is the default guide; a ratio is flagged only when it's sustained rather than a one-week artefact.

Croisier, J.L., et al. (2008). Strength imbalances and prevention of hamstring injury in professional soccer players. American Journal of Sports Medicine, 36(8).

Strength standards

What it means. Where a lift sits relative to body weight, from beginner through elite. Useful for judging whether a number is genuinely strong for you rather than in the abstract.

How we calculate it. Your best estimated 1RM for the lift is divided by your logged body weight and compared to published multiples for that movement. Standards are population reference points — they don't account for limb lengths, training age, or sex, so treat them as orientation rather than a verdict.

Reference multiples adapted from published strength-standard tables used in strength and conditioning practice. These are population reference points, not peer-reviewed thresholds.

A note on limits

Published findings describe group averages, and your response may differ. Targets and scores here are starting points to adjust from, not prescriptions. RepLab provides general training guidance, not medical advice — consult a qualified professional before starting a training programme, especially with an existing health condition.