Movement analysis and its applications

· Movement analysis = a structured way to break down, describe and evaluate movement to improve performance, health, safety, rehabilitation and accessibility.
· IB focus: use a phases-of-movement approach: preparatory phase, force production phase, critical instant, then follow through for discrete skills or recovery for continuous skills.
· Exam answers should link analysis to specific improvements, not just describe what happens.
· Movement analysis can help a coach design a training programme or a physiotherapist design a rehabilitation programme.

Phases-of-movement approach

· Preparatory phase = movements that position the body for effective performance; includes body position, balance, alignment, anticipation and muscle loading.
· Force production phase = the main movement where muscles create force; involves timing, coordination, range of motion, joint action and force direction.
· Critical instant = the key moment that determines success, such as ball contact, release, take-off, landing, catch or strike.
· Follow through = movement after the critical instant in a discrete skill; helps decelerate safely, maintain accuracy, absorb force and reduce injury risk.
· Recovery = return or transition phase in a continuous skill; prepares the body for the next repetition or cycle, such as the next stride, stroke or pedal revolution.
· The critical instant is often easiest to identify, but the preparatory and force production phases often explain why the outcome was successful or unsuccessful.

This image shows a running cycle broken into visible positions, making it useful for identifying force production, critical instant, and recovery in a continuous skill. Students can annotate foot contact, flight, and the return to the next stride. Source

Discrete vs continuous skills

· Discrete skill = clear beginning and end, e.g. tennis serve, golf swing, basketball free throw, javelin throw.
· Discrete skills usually end with a follow through after the critical instant.
· Continuous skill = repeated movement cycle with no clear endpoint, e.g. running, cycling, swimming, rowing.
· Continuous skills usually use recovery rather than follow through, because the performer must reset for the next cycle.
· In exams, state whether the skill is discrete or continuous before naming the final phase.

Applying movement analysis to performance

· Movement analysis helps identify technical strengths and weaknesses in a performer’s movement.
· A coach can compare the performer’s technique with an ideal model, elite performer, previous attempt or biomechanical principle.
· Improvements may target joint position, timing, balance, coordination, range of motion, force application or body alignment.
· Good exam phrase: “The analysis identifies the phase where the error occurs and links this to a specific performance outcome.”
· Example: in a tennis serve, poor preparatory shoulder rotation may reduce force production, lowering racket speed at the critical instant.

Applying movement analysis to health, safety and rehabilitation

· Movement analysis can identify movement patterns that increase injury risk, such as poor landing mechanics, excessive knee valgus, limited range of motion or poor postural control.
· In rehabilitation, physiotherapists can use movement analysis to monitor recovery and decide when an athlete is ready to progress.
· In accessibility, analysis can identify how movement demands can be modified for people with different physical abilities.
· In health settings, analysis can support safer walking, lifting, balance tasks and return-to-activity decisions.
· Strong exam answers link movement analysis to prevention, correction, monitoring and individualized intervention.

This image shows how movement analysis can be performed using technology in a rehabilitation or sport-science setting. It links directly to analysis of force, joint motion, gait, and return-to-play decisions. Source

Qualitative and quantitative analysis

· Qualitative analysis = observation-based judgement, often used by coaches, teachers and therapists.
· Examples: video observation, slow-motion replay, checklist comparison, coach feedback.
· Quantitative analysis = numerical measurement of movement.
· Examples: joint angles, velocity, acceleration, stride length, contact time, force plate data, motion capture.
· Use qualitative analysis for quick practical feedback; use quantitative analysis when objective data improves accuracy.
· Biomechanics uses mechanical principles to study human movement; movement can be assessed and used to infer the forces that caused it.

Exam technique: how to analyse a movement

· Choose the skill and identify whether it is discrete or continuous.
· Break it into the correct phases: preparatory, force production, critical instant, then follow through/recovery.
· For each phase, describe joint actions, body position, balance, timing and force application.
· Identify the main error and the phase where it occurs.
· Explain the consequence for performance, safety, rehabilitation or accessibility.
· Suggest one targeted correction, such as changing technique, strength, mobility, equipment, practice design or feedback.

Common examples

· Basketball free throw: preparatory = stance and ball position; force production = leg extension and arm extension; critical instant = ball release; follow through = wrist flexion and arm extension.
· Long jump: preparatory = approach run; force production = take-off action; critical instant = take-off; follow through/recovery = flight and landing preparation.
· Running: preparatory/force production can be analysed within each stride; critical instant may be foot strike or toe-off depending on the question; recovery = swing phase preparing for the next step.
· Swimming stroke: force production = pull phase; critical instant may be hand entry, catch or push depending on focus; recovery = arm recovery before next stroke.
· Rehabilitation gait analysis: identify asymmetry, reduced range of motion, poor weight transfer or unsafe balance during the movement cycle.