ACI Documentation

Athletic Capacity Index (ACI) — Construct Validity, Norms & References

Version: 

2026.07
(norms stamp persisted on every 
IndexResult
record) Validated age range: 15–59 years Population target: athletic / performance-oriented individuals (teens through 40s)

1. Overview

The Athletic Capacity Index (ACI) is a composite score that summarises four movement capacities into a single 0–98 index:

| Test | Capacity domain | Composite weight | |------|-----------------|-----------------| | VJ — Vertical Jump (cm) | Peak lower-body power | 0.30 | | CMJ30 — 30s countermovement jump power index | Power repeatability / reactive endurance | 0.25 | | SLH — 20s single-leg lateral hop (reps) | Change of direction & agility, with L/R asymmetry penalty | 0.25 | | 60PU — 60s push-ups (reps) | Upper-body muscular endurance | 0.20 |

Each raw test result is converted to a 10–98 sub-index via an age- and sex-specific z-score against the norm tables in §4. The ACI is the weighted sum of the four sub-indices.

2. Construct validity — why these four tests

The ACI is deliberately restricted to field tests that are (a) reliably measurable from video, (b) map onto distinct, theoretically-grounded performance capacities, and (c) minimise redundancy so the composite is not double-counting a single latent factor.

2.1 Peak power — Vertical Jump (VJ)

Vertical jump height is the most widely used field surrogate for lower-body peak mechanical power. The Sargent/reach method measures jump height as the difference between standing reach and peak reach at flight apex; flight-time methods (force plate, contact mat, markerless CV displacement) derive height from flight time. The two read systematically different — flight-time-derived heights are typically ~5–10 cm lower than reach-derived heights for the same athlete [1][2]. This is why the VJ norms below are anchored to the reach method and must not be scored against flight-time data without a documented correction factor (see §5).

2.2 Power repeatability — CMJ30

A 30-second repeated countermovement jump integrates volume (reps) and quality (average jump height) into a power index = 

reps × avg_height_cm
, analogous to the Bosco repeated-jump protocol [3]. It taxes the phosphocreatine and short-term glycolytic systems and exposes the ability to sustain explosive output — a capacity distinct from a single maximal effort (VJ).

2.3 Change of direction & agility — Lateral Hop (SLH)

The 20-second single-leg lateral hop stresses frontal-plane neuromuscular control, rapid force absorption/re-generation, and dynamic balance. Because asymmetry between legs is itself an injury and performance risk factor [4][5], the SLH contribution uses a harmonic Lateral Hop Index (LHI) of left and right good-form reps. The harmonic mean (rather than the arithmetic mean) self-penalises L/R imbalance: a 3-and-3 effort scores the same as a balanced 3-and-3, but a 6-and-0 effort scores far lower, so a one-legged "perfect" trial cannot inflate the index.

2.4 Upper-body endurance — 60s Push-Ups

The 60-second push-up is the standard field test for upper-body muscular endurance in adults [6][7]. Males perform the full (toes) protocol; females perform the modified (knees) protocol, per CSEP-PATH and ACSM conventions. The time cap (60 s) adds a pacing/sustainability dimension distinct from a reps-to-failure test.

3. The composite model

For a raw score 

x
with norm 
(mean, sd)
:

z   = (x − mean) / sd
sub = clamp( 50 + 15·z , 10, 98 )      # 10–98 sub-index

The ACI is the weighted sum of the four sub-indices. Because a weighted average of correlated indices has narrower dispersion than its components, the composite standard deviation is computed (not assumed to be 15):

sd_composite = 15 × √( Σ wᵢ² + 2·r·Σᵢ<ⱼ wᵢ·wⱼ )

with a provisional inter-test correlation r = 0.5, to be re-estimated from accumulated paired-test field data. The percentile of the ACI is then taken from 

z_aci = (ACI − 50) / sd_composite
using the standard normal CDF.

Performance bands

| Band | ACI | |------|-----| | Elite | ≥ 85 | | High Performance | 70–84 | | Competitive | 55–69 | | Developing | < 55 |

4. Normative tables & provenance (norms version 
2026.07
)

For each test the table below gives the mean and standard deviation used to compute the z-score, by sex and age band, together with the source and any adaptation applied.

Convention: mean = midpoint of the "Good" normative band (≈40th–59th percentile); SD = estimated from the band width (≈ band half-width ÷ 1). Where no single authoritative source covered our exact protocol, values were adapted as noted and are flagged provisional pending accumulation of Kinelitics cohort data.

4.1 Vertical Jump (cm) — reach method

| Sex | <20 | 20–29 | 30–39 | 40+ | Source / adaptation | |-----|------|-------|-------|-----|--------------------| | Male | 42 ± 9.0 | 40 ± 8.5 | 35.5 ± 7.5 | 30 ± 7.0 | Reach-method norms adapted from Markovic et al. (2004) [2] and CSEP-PATH adult jump ranges [7]; "Good"-band midpoints. | | Female | 31 ± 7.0 | 28 ± 7.0 | 23.5 ± 6.0 | 19 ± 5.5 | As above, sex-adjusted; consistent with Sargent original ranges [1]. |

⚠️ Method warning: these norms are anchored to the reach (chalk-and-wall) method. Flight-time-derived jump heights read ~5–10 cm lower and must not be scored against this table without a correction factor [1][2].

4.2 CMJ 30s — power index (reps × avg height cm)

| Sex | <20 | 20–29 | 30–39 | 40+ | Source / adaptation | |-----|------|-------|-------|-----|--------------------| | Male | 540 ± 120 | 540 ± 120 | 450 ± 110 | 375 ± 95 | Provisional — derived from typical athletic repeated-jump ranges following the Bosco repeated-jump paradigm [3]; scaled by age-related power decline. | | Female | 378 ± 90 | 378 ± 90 | 310 ± 80 | 247 ± 75 | As above, sex-adjusted to ~70% of male values per established sex power ratios [3][6]. |

4.3 Lateral Hop 20s — single-leg good-form reps (harmonic LHI)

| Sex | <20 | 20–29 | 30–39 | 40+ | Source / adaptation | |-----|------|-------|-------|-----|--------------------| | Male | 38 ± 7.0 | 38 ± 7.0 | 34 ± 7.0 | 29 ± 6.0 | Provisional — based on athletic lateral-hop normative ranges; the harmonic LHI (L+R) is consumed, not the arithmetic mean. Asymmetry methodology per Noyes et al. (1991) and Hewett et al. (2005) [4][5]. | | Female | 31 ± 6.0 | 31 ± 6.0 | 27 ± 6.0 | 23 ± 5.0 | As above, sex-adjusted. |

Note: the capture flow records two 20 s sub-trials (left leg, right leg). 

slh_20s_reps
= harmonic mean of L and R good-form reps. A legacy single-sided record falls back to that single value.

4.4 Push-Up 60s — reps

| Sex | <20 | 20–29 | 30–39 | 40+ | Source / adaptation | |-----|------|-------|-------|-----|--------------------| | Male | 23 ± 5.5 | 23 ± 5.5 | 18.5 ± 4.5 | 15 ± 3.5 | Full (toes) protocol; adapted from CSEP-PATH (2019) and ACSM (2021) adult push-up normative tables [6][7]. | | Female | 21 ± 5.0 | 21 ± 5.0 | 17.5 ± 4.5 | 15 ± 3.5 | Modified (knees) protocol per CSEP-PATH/ACSM sex conventions [6][7]. |

4.5 Cross-source provenance summary

The normative base draws on, and is adapted from:

  • CSEP-PATH (2019) [7] — Canadian adult push-up and jump normative bands.
  • ACSM (2021) [6] — adult muscular-endurance and power test norms.
  • Markovic et al. (2004) [2] — factorial validity and normative ranges for squat/countermovement vertical jump height.
  • Bosco et al. (1983) [3] — repeated-jump power methodology underpinning CMJ30.
  • Noyes et al. (1991) / Hewett et al. (2005) [4][5] — single-leg hop symmetry and neuromuscular-control rationale underpinning the SLH LHI method.
  • China National Fitness Surveillance (2023) — population reference ranges used to sanity-check age-band decline slopes.
  • Myers et al. (2014) — fitness-index construct framing.
  • Kinelitics internal Fitness Index Norms document (2026) — synthesis and calibration document that resolved band midpoints and SD estimates into the numerical table above. Where source bands did not align to our exact protocol (duration, distance, leg, sex protocol), an 
    additional_factor
    / duration-ratio adaptation was applied and is noted per test.

5. Measurement method caveats

  • VJ reach vs flight-time: reach norms are not directly comparable to flight-time/CV-displacement jump heights. A correction factor is required before scoring flight-time data against the table in §4.1.
  • CMJ30 power index requires both rep count and average jump height; a reps-only capture under-scores the index.
  • SLH requires both legs; the harmonic LHI intentionally penalises asymmetry, so a single-leg result must not be treated as representative.
  • 60PU sex protocols differ (full vs modified); a protocol mismatch invalidates the normative comparison.
  • Age outside 15–59: the ACI is not validated outside this range; an age-range warning is emitted on the result record.

6. Scientific references

  1. Sargent DA. The physical test of a man. American Physical Education Review. 1921;26(4):188–194. — origin of the Sargent/reach vertical jump test.
  2. Markovic G, Dizdar D, Jukic I, Cardinale M. Reliability and factorial validity of squat and countermovement jump tests. Journal of Strength and Conditioning Research. 2004;18(3):551–555.
  3. Bosco C, Luhtanen P, Komi PV. A simple method for measurement of mechanical power in jumping. European Journal of Applied Physiology and Occupational Physiology. 1983;50(2):273–282. — basis for repeated-jump (CMJ30) power indexing.
  4. Noyes FR, Barber SD, Mangine RE. Abnormal lower limb symmetry determined by functional hop tests after rupture of the anterior cruciate ligament. American Journal of Sports Medicine. 1991;19(5):513–518. — functional single-leg hop symmetry framework.
  5. Hewett TE, Myer GD, Ford KR, et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict ACL injury risk in female athletes. American Journal of Sports Medicine. 2005;33(4):492–501. — frontal-plane neuromuscular control rationale for lateral hopping.
  6. American College of Sports Medicine. ACSM's Guidelines for Exercise Testing and Prescription. 11th ed. Wolters Kluwer; 2021. — adult muscular-endurance and power test norms; sex-specific push-up protocols.
  7. Canadian Society for Exercise Physiology. CSEP-PATH: Physical Activity Training for Health — Reference Manual. Ottawa: CSEP; 2019. — Canadian adult push-up and jump normative bands.
  8. Moir GL. Vertical jump height from force platform and jump-and-reach: a methodological comparison. Journal of Strength and Conditioning Research. 2008;22(4):1045–1049. — documents the systematic reach-vs-flight-time discrepancy.
  9. Patterson DD, Peterson DF. Vertical jumps and depth jumps: a brief review of the literature. National Strength and Conditioning Association. — jump-test measurement methodology.
  10. Myers J, McAuley P, Froelicher VF, et al. The effect of fitness on all-cause mortality. — construct framing for composite fitness indexing and its relationship to health outcomes.
  11. General Administration of Sport of China / National Fitness Surveillance Centre. National Physical Fitness Surveillance Report. 2023. — population reference ranges used to validate age-band decline slopes.
  12. Kinelitics. Fitness Index Norms (internal calibration document). 2026. — synthesis and band-midpoint/SD resolution into the numerical norms above; provisionally adapted pending Kinelitics cohort data.

7. Versioning & reproducibility

  • The norms stamp 
    2026.07
    is written to the 
    norms_version
    field of each 
    IndexResult
    record so any historical result can be re-scored or audited against the exact norms used at the time.
  • Norms and weights will be re-released under a new stamp as Kinelitics cohort data accumulates and inter-test correlation is empirically estimated.
  • Any change to measurement method (e.g. adopting flight-time jump height) will ship with a documented correction factor and a norms-table update.