How to Measure Throwing Velocity and Power with PoinT GO

Why Measure Throwing Velocity and Power?

A 2020 meta-analysis by Freitas et al. in the Journal of Strength and Conditioning Research analyzed 34 studies and found that medicine ball throw velocity correlates with sport-specific throwing performance at r = 0.71–0.85 across baseball, handball, and volleyball. This makes it one of the highest-validity non-sport-specific performance tests available — and it is far cheaper and safer to standardize in a training environment than radar gun measurements of actual sports throws.

For coaches and athletes, measuring throwing velocity and power serves three distinct purposes:

• Baseline assessment: Establish current upper-body power output for program design decisions — specifically whether the athlete's force-velocity profile is deficient in peak force, peak velocity, or both.
• Progress monitoring: Verify that upper-body training is producing adaptation every 3–4 weeks without requiring maximal sport-specific throws during training cycles.
• Readiness screening: Pre-session throw velocity compared to a rolling baseline sensitively detects neuromuscular fatigue in the upper-body kinetic chain — important for overhead-dominant athletes managing pitch count or serving volume.

The Physics: From Arm Speed to Ball Velocity

Ball release velocity is the product of an integrated kinetic chain, not arm strength in isolation. The proximal-to-distal sequence — legs generate ground reaction force, hip rotation transfers momentum to the trunk, scapular stabilizers transmit force to the arm, wrist and finger flexors apply the final acceleration impulse — means that weaknesses anywhere in the chain cap release speed.

The relevant physics: peak power output (P) during the throwing motion equals the product of the mean force applied to the ball and its acceleration path length. Longer acceleration paths (a fuller arm swing or medicine ball chest pass with full hip extension) theoretically allow more total impulse. This is why research consistently finds that medicine ball chest pass velocity correlates more strongly with 1RM bench press than it does with isolated wrist strength (Newton et al., 1997).

IMU-based measurement captures the acceleration profile of the implement being thrown — either the IMU attached to the ball or worn on the wrist/forearm. The peak linear acceleration during the push phase, integrated over time, yields an impulse estimate from which peak power is derived. Accuracy of wrist-mounted IMU vs. radar gun: mean error of 4–7% for standardized throws when mount position is controlled (Cormack et al., 2015).

Test Protocols by Throw Type

Three standardized throw types provide complementary information about different segments of the upper-body force-velocity spectrum:

Testing rules to standardize results: (1) Standardize foot position with tape markers; (2) Record the fastest 3 of 5 attempts; (3) Test at the same time of day and same warm-up state across sessions; (4) Use the same ball mass — even 0.5 kg differences shift velocity results by 3–6%. A standardized warm-up of 10 minutes general activity, 5 progressive submaximal throws at 60%, 80%, and 95% effort before the measured attempts ensures peak performance readiness.

IMU Measurement Setup and Placement

For IMU-based throw measurement with PoinT GO, two placement options exist depending on the throw type and testing goal:

Wrist/Forearm Mount

Strap the PoinT GO sensor to the dominant forearm, 3–5 cm proximal to the wrist, with the primary measurement axis aligned with the forearm's long axis. This placement captures the distal end-point velocity of the throwing arm — a close proxy for ball release velocity in linear throws (chest pass, overhead). Correlation with radar gun for this mount: r = 0.87 (standardized chest pass, Cormack et al., 2015).

Ball Attachment

For rotational throws and cases where maximum accuracy is required, attach the PoinT GO sensor to the medicine ball using the provided mount or adhesive pad. This directly measures the ball's kinematic profile. Requires a slightly heavier test ball to maintain dynamics (add 200–300g for the sensor mass). Correlation with radar: r = 0.93 for rotational throws.

Key setup checklist:

• Sensor orientation confirmed (axis alignment verified in app before testing)
• Bluetooth connection stable — test two throws in practice mode before recording session
• Arm swing plane consistent — coaching cue: "push directly through the target, not upward"
• Record ambient conditions (temperature affects joint temperature and muscle viscosity — morning vs afternoon testing can shift results 4–6%)

Normative Values and Performance Benchmarks

The following norms are derived from the Freitas et al. (2020) meta-analysis and athlete population studies for adult male athletes. Female athletes show approximately 20–30% lower absolute values with similar sport-specific relative differences.

More useful than absolute norms is comparing the chest pass to rotational throw ratio. A chest-pass-dominated profile (rotational throw <10% faster than chest pass) suggests underdeveloped hip-to-trunk power transfer — direct the training intervention toward hip rotation and anti-rotation core work. A rotational-dominant profile with lagging chest pass suggests horizontal push strength is limiting the upper limb's contribution.

Training Applications Based on Throw Data

Baseline throw testing reveals which segment of the force-velocity curve is limiting performance. The intervention design follows directly from the test profile:

• Low chest pass velocity relative to bench press strength: Force capacity exists but power expression is limited. Priority: ballistic push press, medicine ball variations, and resisted explosive pushing movements at 30–40% 1RM with maximal acceleration intent.
• Proportionally low rotational throw: Hip and trunk power transfer is the limiter. Priority: hip extension power (hang cleans, kettlebell swings, hip thrusts), anti-rotation press variations, and rotational medicine ball work against a wall.
• High lateral asymmetry (dominant vs. non-dominant side >15% on rotational throw): Increase unilateral rotational work on the weaker side. Asymmetries of this magnitude predict elevated injury risk at the shoulder and elbow over a competitive season (Garrison et al., 2015).

Re-test every 3–4 weeks to quantify training response and update the intervention if needed. Meaningful improvements in trained athletes: >0.3 m/s on chest pass, >0.5 m/s on rotational throw over 6 weeks of targeted training.

Longitudinal Tracking and Retesting

For throw testing to provide actionable intelligence, consistency of protocol is non-negotiable. Variable warm-up, different ball masses, or inconsistent foot placement can generate test-retest variability that exceeds real adaptation signals. Build a standard operating procedure and document it:

• Same ball, same mount/attachment method, same room temperature if indoor
• Same warm-up protocol preceding every test session (suggested: 5 min light cardio, 3×5 progressive submaximal throws)
• Same time of day ±1 hour (diurnal variation in neuromuscular output is 5–8%)
• Minimum detectable change for chest pass: 0.25 m/s (95% confidence, coefficient of variation ~4%)

Plot your mean best-of-3 velocity over time. An upward trend of 0.2–0.4 m/s per 4-week block confirms that upper-body power training is producing meaningful transfer. A plateau despite consistent training signals a need to address a different limiting factor — most commonly either general strength (if throw velocity ceiling is below the recreational norm) or recovery quality (if plateau coincides with high training load periods).