Throwing is a whole-body, high-speed action split into six clear phases of throwing: wind-up, early cocking, late cocking, acceleration, deceleration and follow-through. Mastering each phase keeps velocity high, cuts injury risk and sharpens control.
Quick look at the six phases
|
Phase |
Key aims |
Main muscle focus |
Typical injury risks |
|
Wind-up |
Rhythm & balance |
Core, gluteals |
Rare |
|
Early cocking / stride |
Store energy, lengthen step |
Deltoid, rotator-cuff preparatory activity |
Minimal |
|
Late cocking |
Max external rotation, elastic load |
Supraspinatus, infraspinatus, teres minor |
UCL strain, internal impingement, SLAP tear |
|
Acceleration |
Explosive release |
Subscapularis, pectoralis major, latissimus dorsi, triceps, serratus anterior |
Little time for injury but very high forces |
|
Deceleration |
Braking & energy dissipation |
Posterior cuff, biceps, brachialis |
Highest joint load – cuff strain, SLAP, biceps tendon damage |
|
Follow-through |
Re-balance & fielding stance |
Low muscle demand |
Uncommon |
Why the kinetic chain matters
- Power starts from the legs, travels through the trunk and finishes at the fingers – a linked kinetic chain.
- A 20 % drop in hip-trunk energy makes the shoulder work 34 % harder to throw the same speed.
- Common breakdowns
- Early pelvic turn – arm lags behind, shoulder load soars.
- Closed stride foot – trunk rotation blocked, accuracy suffers.
Biomechanics in brief
|
Variable |
Why it helps velocity |
|
↑ Shoulder external rotation (≈ 170 °) |
Longer arc for acceleration |
|
Fast pelvis & trunk rotation (400–700 ° s⁻¹) |
Builds angular momentum |
|
Forward trunk tilt (≥ 30 ° at release) |
Transfers force in line with throw |
Screening tip: pitchers whose throwing arm lacks at least 5 ° of extra external rotation face almost double the risk of shoulder or elbow injury.
Injury hotspots & prevention
Shoulder
- Rotator-cuff overload (late cocking & deceleration)
- Internal impingement from extreme external rotation
Elbow
- UCL strain under peak valgus torque in late cocking
Simple safeguards
- Year-round cuff and scapular-stability circuit (elastic bands, prone Ys/Ts)
- Hip and core strength to keep the chain connected
- Seasonal workload checks – not just pitch counts but total weekly throws
- Regular range-of-motion screening for GIRD and external-rotation deficits
See our Rotator Cuff Related Shoulder Pain guide for detailed home-exercise videos.
Training tips that stick
- Plyometrics: medicine-ball wall throws, overhead slams – mimic game speed.
- Strength blocks: deadlifts, split squats, anti-rotation presses build the engine.
- Mechanics drills: slow-motion “pivot picks” and step-behind throws to groove timing.
- Progressive long-toss: extend distance only when pain-free and mechanics hold.
Mind over shoulder – psychology tools
|
Tool |
How to use |
|
Mindful breath (5-in / 5-out) |
Two cycles on the rubber to settle arousal |
|
Visualisation |
Picture the pitch flight before each rep |
|
3 R’s – recognise, regroup, refocus |
Snap out of negative self-talk mid-game |
|
Post-game debrief |
Write two positives and one tweak within 30 minutes |
Regular mindfulness cuts pre-throw muscle tension and sharpens proprioception, improving both speed and control.nhs.uk
Clinical pearls / Key points
- Late cocking and deceleration carry most joint load – strengthen for braking, not just power.
- Efficient kinetic chain means smooth, not necessarily hard, arm action.
- External-rotation deficit is an early red flag for in-season injury.
- Simple mental cues (“tall, fall, finish”) keep mechanics consistent under pressure.
Patient FAQs
Is long-toss safe for juniors?
Yes – if distances rise gradually, mechanics stay solid, and soreness clears by next session.
Do weighted balls boost velocity?
They can, but only in short blocks and alongside robust cuff, scapular and core work.
Why does my elbow hurt only after games?
Post-game ache often comes from deceleration overload and fatigue. Add forearm flexor strength and review pitch volume.
Call to Action
If you have pain, book an appointment to be reviewed by Prof Imam or another member of our specialist team at The Arm Clinic. Early specialist care helps prevent long-term issues. Visit www.TheArmDoc.co.uk or book your consultation today. Phone: 020 3384 5588 | Email: Info@TheArmDoc.co.uk
Disclaimer
The information provided here supports, but does not replace, advice from a registered healthcare professional. The content reflects UK guidance as of July 2025