Netball Landing Error Screening Protocol: Scoring Knee Valgus Risk on Video

A wing defence intercepts a pass inside the circle, plants on one leg, and has exactly one step before the footwork rule forces her to stop dead. Her knee buckles inward for a fraction of a second, she recovers, and play continues. Nobody stops the drill. Nobody writes anything down. Three weeks later the same knee gives way on an almost identical landing during a match, and the review video shows the same valgus collapse nobody flagged in training.

That gap — between a visible landing fault and a documented risk score — is what a landing error screening protocol is supposed to close. Most jump-landing screens were built and validated on a bilateral drop vertical jump, which is not the movement that actually injures netball knees. Netball's footwork rule forces single-leg decelerations and forced stops that basketball or volleyball players rarely have to perform under the same time pressure. This guide sets out a netball-specific screening battery: three landing tasks that reproduce match demands, a video scoring method adapted from validated 2D valgus assessment, and a documentation protocol a coach or physio can run pitch-side with two phones and a tripod.

Why Generic Landing Screens Undersell Netball Risk

The two studies this protocol borrows its methodology from were both built on team-sport samples dominated by basketball, soccer, and volleyball, using a bilateral drop vertical jump as the standard task. Netball's laws create a different mechanical problem. A player who lands on one foot must establish it as the landing foot and pivot on it; a player landing on both feet simultaneously must choose a pivot foot immediately. Either way, the deceleration happens inside a single ground contact — there is no second step available to redistribute force, the way there is in basketball's gather step or a soccer player's continued run-through.

Combine that rule with netball's high frequency of airborne interceptions, rebounds off the ring, and sudden marking stops, and single-leg, high-velocity, forced-stop landings stop being an occasional event and become the dominant landing pattern of a match. Netball is repeatedly flagged in female team-sport injury surveillance as carrying one of the higher non-contact ACL injury rates, with landing and change-of-direction mechanisms — not direct contact — accounting for the large majority of cases. A screening tool that only tests bilateral, unpressured landings misses the specific mechanical moment where netball's ACL injuries actually happen.

Equipment and Camera Setup

The protocol needs two camera angles, not one. A single anterior view cannot reliably separate genuine frontal-plane knee valgus from a trunk lean that only looks like it from straight on.

• Frontal camera: 3 m directly in front of the landing zone, lens height at the athlete's knee, capturing at 120 fps minimum — most current smartphones set to their slow-motion mode will give a clean 240 fps for frame-by-frame review.
• Sagittal camera: 3 m to the side, same height, used to confirm hip and knee flexion depth and rule out a stiff-legged landing strategy that a frontal view alone would miss.
• Court marking: tape an X on the landing zone and a takeoff line 1.5 m back, so every trial lands in the same spot relative to both cameras.
• Lighting: standard overhead gymnasium lighting is usually adequate at 120 fps; avoid pointing the frontal camera toward a bright window or door.

Two tripods and two phones running native slow-motion camera apps are sufficient. No specialized motion-capture software is required for the scoring method below — that is the entire point of building the protocol around a 2D projection angle rather than a 3D kinematic model.

The Three-Task Netball Landing Battery

Each single-leg task is performed for 3 trials per leg; the two-foot task is performed for 3 trials total, giving 9 scored landings per athlete. Allow full recovery between trials — this is a screening task, not a fatigue test, and fatigued mechanics will inflate the score in a way that has nothing to do with baseline risk.

Score every trial live if you can, but keep the raw footage regardless. Re-reviewing borderline trials at 0.25x speed catches errors a live view misses, particularly in the first 100 milliseconds after ground contact, which is roughly when peak knee abduction moment tends to occur.

Scoring Method: FPPA and the Netball Landing Score

The measurement underneath this protocol is the frontal plane projection angle (FPPA) — the angle, on the frozen frame at peak knee flexion, between a line from the anterior superior iliac spine to the mid-patella and a line from the mid-patella to the mid-ankle. McLean, Walker, Ford, Myer, Hewett, and van den Bogert (2005, British Journal of Sports Medicine) validated this 2D video measurement against 3D motion capture as a screening proxy for knee abduction loading, reporting a moderate-to-strong correlation of roughly r = 0.71 between the 2D angle and the true 3D valgus angle. That is not a substitute for laboratory kinematics — a 2D angle cannot capture out-of-plane hip rotation, which is a real limitation — but it is accurate enough to separate concerning landing mechanics from clean ones, using equipment every training venue already owns.

For each of the 9 scored trials, mark the frame at peak knee flexion on the frontal camera and record one of the following:

• 0 points — knee tracks over or lateral to the second toe, FPPA under 8°
• 1 point — mild medial knee displacement, FPPA 8–15°
• 2 points — moderate displacement, FPPA 15–20°, or a visible trunk lean toward the plant leg
• 3 points — severe collapse, FPPA over 20°, or a visible balance loss / knee buckle requiring a corrective step

Sum the 9 trial scores into a composite Netball Landing Score out of 27. The checklist logic deliberately mirrors the Landing Error Scoring System (LESS), the 17-item bilateral drop-jump checklist that Padua and colleagues (2009, American Journal of Sports Medicine) validated against a 3D-derived composite risk score at r = 0.84, with strong inter-rater reliability (ICC 0.84) and intra-rater reliability (ICC 0.91). The original LESS was built and validated for a two-footed drop vertical jump only — it has never itself been validated on single-leg or sport-specific reactive tasks. That is exactly the gap this netball-adapted, three-task version is trying to close, and the trade-off is honest: it inherits LESS's scoring logic but not its validation data.

Interpreting the Composite Score

These bands are a practical, adapted threshold built for pitch-side decision-making, not a peer-reviewed cut-score from a prospective injury study — treat them as a triage tool rather than a diagnosis. One flag matters more than the composite total: any single trial scoring a 3 (visible knee buckle) on the single-leg lateral catch-and-stick task, regardless of where the rest of the composite lands. That task most closely reproduces the mechanism behind the majority of documented netball ACL injuries, and one severe fault there is a stronger signal than an evenly moderate spread across all nine trials.

Coaching Cues That Actually Change the Landing

Scoring without a corrective plan just produces a spreadsheet nobody looks at again. Three fault patterns show up repeatedly, and each responds to a different fix. Knee-in on the plant leg responds better to a cue like push the knee out over the little toe than to don't let your knee cave — cueing what to do outperforms cueing what to avoid in live coaching sessions, and that difference alone has moved athletes from a 2 to a 0 on individual trials within a single session. A stiff-legged landing, visible on the sagittal camera as limited hip and knee flexion, responds to a quiet landing cue — athletes who chase silence on contact almost always add flexion to get there without being told to. A trunk lean toward the plant leg on the rebound task is usually a hip abductor and lateral core control problem rather than a knee problem, and correcting the knee cue alone rarely fixes it.

A simple progression that works for all three: mini-band lateral walks emphasizing knee tracking over the toes, single-leg RDLs with a contralateral reach for eccentric control, then reintegration into the exact netball landing task at reduced approach speed before returning to full training volume. Skipping the reduced-speed step and going straight back to game-speed drills is the single most common reason a corrected pattern breaks down again under match pressure.

Screening Schedule and Documentation

Pre-season, 3 weeks before the first fixture: run the full 9-trial battery on every player in the squad. In-season: rescreen any athlete scoring moderate or above every 4 weeks until the composite drops below threshold. Return to netball-specific training after injury: the full battery is mandatory before clearance to unrestricted match minutes, regardless of where the medical clearance timeline sits — a cleared knee and a knee that passes this screen are not automatically the same thing.

Record, per session: date, assessor, per-trial score and estimated FPPA, composite total, a reference to the saved video clip, and any corrective exercises prescribed. Track the composite trend across the season rather than treating each screen as an isolated event — a score that rises after a previous improvement usually tracks a training load spike or accumulated fatigue rather than a genuine technique regression, and that distinction should send you to the load log before it sends you back to more corrective drilling.