Countermovement Jump Test: Complete Protocol & Norms

The countermovement jump (CMJ) test is the most widely used field test in sport science and high-performance athletics. Its simplicity belies its depth — a single CMJ produces a cascade of metrics (jump height, flight time, ground contact characteristics, power, rate of force development) that together paint a comprehensive picture of neuromuscular readiness, explosive power, and fatigue status.

This guide covers the complete CMJ test protocol, key metrics beyond raw jump height, sport-specific normative data, and how to use CMJ testing as part of a systematic athlete monitoring program.

Definition

The countermovement jump is a two-footed vertical jump preceded by a rapid downward movement (countermovement). The countermovement loads the stretch-shortening cycle — the athlete's muscles and tendons store elastic energy during the rapid eccentric loading, which is then released in the subsequent concentric (jumping) phase. This is why CMJ height typically exceeds squat jump height by 10–25%.

Why CMJ Is the Preferred Jump Test

The CMJ is preferred over the squat jump for most athletic contexts because it mirrors the mechanics of real sport movements — sprinting, cutting, rebounding, and blocking all involve rapid eccentric-to-concentric transitions. The squat jump (no countermovement) isolates pure concentric power but is less ecologically valid for most sports.

CMJ Variants

• Free arm swing CMJ: Most ecologically valid — arms swing naturally. Higher scores but more variable technique.
• Hands-on-hips CMJ: Most reproducible — removes arm swing variability. Best for detecting small changes in leg power over time.
• Loaded CMJ: Performed with additional load (vest or barbell). Used for power testing at various force-velocity positions.

Equipment

• Force plate (laboratory standard) OR IMU wearable sensor (field standard) OR timing mat (minimum acceptable)
• Non-slip, firm surface
• Standardized footwear across all testing sessions

Pre-Test Standardization

• Test at the same time of day (±1 hour) — CMJ height varies by up to 4–6% across the day
• 24–48 hours after the last intense training session for monitoring purposes
• Record footwear, bodyweight, and testing device for each session
• Standardize arm protocol (free arm vs. hands on hips) and stick to it across all tests

Warm-Up

1. 5 minutes light cardio (cycling or jog)
2. 10 bodyweight squats
3. 5 leg swings each direction
4. 3 submaximal CMJs (60%, 80%, 90% effort), 30 seconds rest between

Test Execution

1. Athlete stands on the measurement device (or in measurement zone if using video/sensor), feet shoulder-width apart.
2. Arms: either on hips (hands-on-hips protocol) or at sides ready to swing (free arm protocol).
3. On command, athlete performs a rapid downward countermovement to approximately 90° knee flexion, then jumps maximally.
4. Athlete should land in approximately the same position as takeoff — knees soft on landing.
5. Record jump height (or flight time for mat-based systems).
6. Perform 3–5 trials with 60–90 seconds rest between trials.
7. Report the best single trial for performance benchmarking; report the average of all trials for monitoring applications.

Jump Height

The primary outcome. Calculated from flight time (h = g × t²/8) or directly from IMU/force plate data. Represents peak lower-body explosive power in the vertical plane.

RSI-Modified (RSImod)

RSImod = Jump Height ÷ Movement Time (from start of countermovement to takeoff). Unlike traditional RSI (used for drop jumps), RSImod captures both the depth and speed of the CMJ, making it a more sensitive measure of neuromuscular readiness than jump height alone.

Contraction Time

The time from the start of the countermovement to takeoff. Shorter contraction times indicate a faster, more efficient stretch-shortening cycle. Elite athletes typically show shorter contraction times than recreational athletes for comparable jump heights.

Peak Power (force plate derived)

The peak instantaneous power output during the concentric phase. Allometrically scaled peak power (W/kg^0.67) accounts for body mass differences across athletes and is the preferred metric for comparing athletes of different sizes.

Force-Time Characteristics

With force plate data, the force-time curve reveals: rate of force development (how quickly force rises), braking impulse (eccentric loading quality), propulsive impulse (concentric drive), and landing force (key for monitoring fatigue-related technique changes). These sub-metrics are available with force plate systems but not standard timing mats.

Bilateral Asymmetry

With dual force plates, left/right force production asymmetry can be quantified. Asymmetry >10% is associated with increased injury risk in team sport athletes. Single-plate or timing mat setups cannot detect bilateral asymmetry.

CMJ Height — Male Athletes

• Basketball (NBA/elite): 72–85 cm
• American football (NFL combine): 85–100 cm (with approach)
• Soccer (professional): 55–70 cm
• Rugby (professional): 50–65 cm
• Olympic sprinters: 65–80 cm
• Recreational male athletes: 35–55 cm

CMJ Height — Female Athletes

• Volleyball (elite): 45–60 cm
• Basketball (WNBA/elite): 42–55 cm
• Soccer (professional): 38–50 cm
• Track sprinters: 40–55 cm
• Recreational female athletes: 25–42 cm

Age-Related Decline

CMJ height typically peaks at ages 20–28, then declines approximately 2–3% per decade in recreational athletes. Well-trained masters athletes (50–60 years) can maintain CMJ values close to their 30-year-old counterparts through continued plyometric and strength training.

Why CMJ Detects Fatigue

The CMJ is sensitive to neuromuscular fatigue because it requires rapid, maximal force expression — exactly the quality that degrades first under fatigue. Metabolic or peripheral fatigue (sore muscles, depleted glycogen) suppresses CMJ height predictably and reversibly.

Individual Baseline Method

Establish each athlete's personal CMJ baseline over 5–10 measurements across non-fatigued conditions. Calculate the mean and standard deviation. Flag for load management when daily CMJ is more than 1 SD (or a fixed threshold of 5%) below baseline.

Threshold Guidelines

• >5% drop from baseline: Mild fatigue — monitor closely, consider modifying the session
• >10% drop from baseline: Significant fatigue — reduce session intensity/volume by 30–50%
• >15% drop from baseline: High fatigue — consider rest day or active recovery only

Monitoring Protocol

Test 3 CMJ trials at the start of every training session (after warm-up). Takes under 5 minutes. Use RSImod rather than jump height alone — it is more sensitive to changes in neuromuscular fatigue at early stages. Track weekly averages to detect cumulative fatigue across training blocks.

Return-to-Training After Illness or Injury

CMJ monitoring is particularly valuable during return-to-training phases. Do not progress loading until CMJ returns to within 5% of pre-illness/injury baseline. This provides an objective criterion that complements subjective wellness scores. 이와 관련하여 How to Test Athletic Power: Complete Testing Battery Guide도 함께 읽어보시면 더 많은 도움이 됩니다.