Maya Chen

Volleyball · 9/2/2026 · KRS-27 phantom scaled

Legacy Z25 teaching reference. The KRS-27 values have not been independently sourced or validated. Bands and indices below are illustrative, not muscle diagnoses, clinical thresholds or treatment recommendations.

Illustrative index

75/100

Symmetry SI

1.8%

Phantom index

BMI (descriptive)

22kg/m²

Cartography

Sage fill scales with stature-adjusted z versus KRS-27.

Regional development

Bilateral symmetry

Deltoid

2.3%

Upper arm

2.8%

Forearm

1.7%

Thigh

1.6%

Calf

1.1%

Rear deltoid

2.2%

Latissimus

2.3%

Triceps

2.2%

Gluteal

0.8%

Hamstring

1.5%

Zone table

Zone	cm	Scaled	z	Band
Chest Width	29.4	29.8	0.77	Upper demo band
L Deltoid	33.8	34.2	1.27	Upper demo band
R Deltoid	34.6	35.0	1.60	Above demo reference
L Upper Arm	28.1	28.5	0.76	Upper demo band
R Upper Arm	28.9	29.3	1.13	Upper demo band
L Forearm	23.2	23.5	0.73	Upper demo band
R Forearm	23.6	23.9	1.00	Upper demo band
Waist	69.4	70.3	0.31	Near demo reference
Chest Circ.	89.8	91.0	0.82	Upper demo band
L Thigh	56.2	56.9	0.51	Near demo reference
R Thigh	57.1	57.8	0.72	Upper demo band
L Calf	35.8	36.3	0.90	Upper demo band
R Calf	36.2	36.7	1.07	Upper demo band
Upper Traps	36.4	36.9	0.87	Upper demo band
L Rear Delt	32.1	32.5	0.96	Upper demo band
R Rear Delt	32.8	33.2	1.28	Upper demo band
L Lat Width	26.2	26.5	0.83	Upper demo band
R Lat Width	26.8	27.1	1.12	Upper demo band
L Tricep	27.4	27.8	0.79	Upper demo band
R Tricep	28.0	28.4	1.08	Upper demo band
Lower Back	74.2	75.2	0.54	Near demo reference
L Glute	94.8	96.0	0.86	Upper demo band
R Glute	95.6	96.8	1.01	Upper demo band
L Hamstring	54.6	55.3	0.53	Near demo reference
R Hamstring	55.4	56.1	0.73	Upper demo band

Proportionality ratios

Waist : chest0.77
Descriptive girth ratio. No validated target or performance inference.
Thigh : calf1.57
Descriptive girth ratio. No validated target or performance inference.
Quad girth : ham girth1.03
Descriptive girth ratio. No validated target or performance inference.
Arm : chest0.32
Descriptive girth ratio. No validated target or performance inference.
Gluteal : waist1.37
Descriptive girth ratio. No validated target or performance inference.

Interpretation boundary

Automated exercise prescriptions are disabled. Girth measurements do not establish muscle strength, activation, injury risk or a need for treatment.

Methods note

Measured girths are retained in centimetres. Scaled values use a stature reference of 170.18 cm. The legacy KRS-27 comparison table is unverified; use it only to demonstrate calculations, not as a normative population.