01
Athlete Profile
02
Image Capture Guide
2–4 stills from the final 2 strides of a maximal 30 m sprint (20–40 m phase)
03
Sprint Mechanics Assessment — S-MAS
Tap a fault if it is PRESENT (Yes = 1)
04
Performance Integration — GPS / StatSports
Optional · powers the full 0–100 Hamstring Risk Index
S-MAS0Excellent
HSRS / 260Very Low
HRI / 1000Green
05
Longitudinal Monitoring
Save assessments to track trends across weeks, months & RTP phases
HRI Trend (0–100)
S-MAS & HSRS Trend
Assessment History
06
Scoring Reference & Methodology
S-MAS Classification
| Score | Rating |
|---|
| 0–1 | Excellent |
| 2 | Good |
| 3–5 | Average |
| 6 | Poor |
| 7–11 | Very Poor |
| 12+ | Extremely Poor |
HSRS Risk Classification
| HSRS | Risk Level |
|---|
| 0–4 | Very Low |
| 5–8 | Low |
| 9–13 | Moderate |
| 14–18 | High |
| 19–22 | Very High |
| 23–26 | Extreme |
Hamstring Risk Weights
×3 High×2 Moderate
×1 Lower— S-MAS only
High (×3): Anterior Pelvic Tilt · Lumbar Extension · Excessive Thigh Separation · Excessive Backside Mechanics · Overstriding
Moderate (×2): Forward Lean · Trunk Rotation · Poor Knee Recovery · Poor Shin Angle
Lower (×1): Vertical Collapse · Poor Foot Inclination · Back Kick
Max HSRS = 26 (5×3 + 4×2 + 3×1)
Hamstring Risk Index (HRI 0–100)
| Component | Weight |
|---|
| Technical Hamstring Risk (HSRS) | 40% |
| Sprint Exposure | 20% |
| High-Speed Running Exposure | 20% |
| Neuromuscular Load | 20% |
Green 0–39
Amber 40–64
Red 65–100
Methodology Notes
The S-MAS is a binary fault count from 2–4 still frames of the final strides of a maximal sprint (toe-off, maximum vertical projection, late swing, touch-down, mid-stance). The HSRS re-weights faults by their association with hamstring strain mechanics, with terminal-swing and overstriding faults carrying the greatest weight because peak biceps femoris musculotendon length and eccentric demand occur in late swing and at braking foot contact. Sprint & HSR exposure sub-scores use the acute:chronic workload ratio (ACWR) framework (acute week ÷ 4-week chronic average); a ratio of ~0.8–1.3 is treated as lowest-risk. Neuromuscular-load sub-score blends inter-limb asymmetry with deceleration loading. The HRI re-normalises across whichever components have data so a technical-only index is still valid.
HSRAS is an evidence-informed screening and monitoring aid for qualified sports-science, S&C and medical practitioners. It does not diagnose injury, replace clinical judgement, or guarantee outcomes. All thresholds (ACWR bands, asymmetry cut-offs, exposure scores) should be calibrated to the individual athlete, squad norms and the methodological limits of the underlying literature, which remains debated. Return-to-play decisions must be made by the responsible medical team.