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Swimming

Swimming is a full-body, low-impact cardiovascular activity that primarily emphasizes upper body pulling strength, shoulder mobility, and aerobic endurance. It develops powerful lats, shoulders, and core while demanding exceptional shoulder range of motion and rotational control.

Quick Reference​

AspectDetails
Primary MusclesLatissimus dorsi, deltoids (anterior/medial), pectorals, triceps, core (rectus abdominis, obliques)
Secondary MusclesBiceps, forearms, hip flexors, quadriceps (kicking), glutes
Energy SystemsPrimarily aerobic (60-90%), ATP-PC and glycolytic for sprints
Common InjuriesSwimmer's shoulder (impingement), rotator cuff tendinopathy, low back pain

Muscles Trained​

Primary Muscles​

Role: Primary pulling muscle in all strokes, responsible for arm adduction and extension through water

Activation Level: Very High (80-95% in freestyle and butterfly pull phase)

Stroke-Specific Notes:

  • Freestyle: High activation during catch and pull-through phases
  • Backstroke: Continuous activation throughout arm cycle
  • Butterfly: Maximal activation during simultaneous pull
  • Breaststroke: Lower activation compared to other strokes

Training Implications: Often becomes overdeveloped relative to opposing muscles, contributing to rounded shoulder posture

Secondary Muscles​

Role: Assist during catch phase, maintain optimal elbow angle, grip water

Activation Level: Moderate (40-60%)

Function: Biceps work with brachialis during high-elbow catch position; forearm flexors and extensors control hand pitch and feel for water

Stabilizers​

Role: Stabilize humeral head in glenoid socket during high-velocity arm movements

Activation Level: Moderate continuous (40-60%)

Key Muscles:

  • Supraspinatus: Initiates arm abduction during recovery
  • Infraspinatus/Teres minor: External rotation during recovery (often weak in swimmers)
  • Subscapularis: Internal rotation during pull phase (often overactive)

Training Implications: High injury risk area; external rotators typically need strengthening to balance overdeveloped internal rotators

Joints Involved​

Shoulder (Glenohumeral Joint)​

Demand Level: Very High - most stressed joint in swimming

Primary Movements:

  • Flexion/Extension: Full range during arm cycle (especially freestyle and backstroke)
  • Internal/External Rotation: Continuous rotation through stroke phases
  • Horizontal Abduction/Adduction: During pull and recovery
  • Circumduction: Complete circular motion in all strokes

Mobility Requirements:

  • Exceptional internal rotation (often 70-90 degrees)
  • Good external rotation (40-60 degrees) though often limited in swimmers
  • Full overhead flexion (180 degrees)

Common Issues:

  • Internal rotation bias: Swimmers develop excessive internal rotation, limited external rotation
  • Anterior instability: Repetitive overhead motion can stretch anterior capsule
  • Impingement: Poor scapular control and muscle imbalances lead to subacromial impingement
  • High repetition: Elite swimmers may perform 1+ million shoulder rotations per year

Hip Joint​

Demand Level: Moderate to High (stroke-dependent)

Primary Movements:

  • Flexion/Extension: Flutter and dolphin kicks
  • Abduction/Adduction: Breaststroke kick cycle
  • Internal/External Rotation: Body roll in freestyle and backstroke

Mobility Requirements:

  • Good hip extension for streamlined body position
  • Excellent abduction and external rotation for breaststroke (frog kick)
  • Hip flexor flexibility to prevent compensatory lumbar extension

Ankle Joint​

Demand Level: Moderate

Primary Movements:

  • Plantarflexion: Primary position for effective kick propulsion
  • Inversion/Eversion: Minor adjustments for blade-like foot position

Mobility Requirements:

  • Exceptional plantarflexion range (pointed toe position)
  • Limited dorsiflexion needed compared to running

Common Issues:

  • Limited plantarflexion reduces kick efficiency
  • Ankle stiffness in former swimmers transitioning to land sports

Energy Systems​

Aerobic System (Oxidative)​

Primary System: 60-90% of energy in most swimming training

Time Domain: Sustained efforts over 2-3 minutes

Characteristics:

  • Distance swimming: 400m+, steady-state efforts
  • Fuel sources: Primarily fat oxidation at lower intensities, increasing carbohydrate use at higher intensities
  • Lactate threshold work: 1500-3000m continuous swims at moderate intensity
  • Recovery between sets: Aerobic system clears lactate

Training Implications: High volume of aerobic training develops mitochondrial density, capillarization, and stroke efficiency

Glycolytic System (Anaerobic)​

Contribution: 20-40% in middle-distance events (100-400m)

Time Domain: High-intensity efforts lasting 30 seconds to 2-3 minutes

Characteristics:

  • 200m-400m races: Significant glycolytic contribution
  • Lactate production: High accumulation in fast-twitch muscle fibers
  • Burn sensation: Characteristic muscle burn from lactate and acidosis
  • Interval training: Common training format (8x100m with rest)

Training Implications: Improves lactate tolerance and buffering capacity

ATP-PC System (Phosphagen)​

Contribution: 30-50% in sprint events (50m and starts/turns)

Time Domain: Maximal efforts under 10-15 seconds

Characteristics:

  • 50m sprints: Heavy reliance on stored ATP and creatine phosphate
  • Explosive starts and turns: Immediate energy for dive and pushoff
  • Very short rest: System recovers quickly (80% in 30 seconds)

Training Implications: Sprint work develops power output and fast-twitch fiber recruitment

Energy System Integration​

Event-Specific Breakdown:

  • 50m sprint: 50% ATP-PC, 40% glycolytic, 10% aerobic
  • 100m sprint: 30% ATP-PC, 50% glycolytic, 20% aerobic
  • 200m: 15% ATP-PC, 45% glycolytic, 40% aerobic
  • 400m-800m: 5% ATP-PC, 35% glycolytic, 60% aerobic
  • 1500m+: Under 5% ATP-PC, 15% glycolytic, over 80% aerobic

Common Imbalances​

Overdeveloped Internal Rotators​

Muscles Affected: Latissimus dorsi, pectoralis major, subscapularis, anterior deltoid

Mechanism:

  • All swimming strokes emphasize internal rotation and pulling motions
  • Lats pull arm down and back with internal rotation bias
  • Anterior shoulder structures work continuously through stroke cycles
  • Repetitive overhead motion in internally rotated position

Manifestation:

  • Shoulders round forward at rest
  • Palms face backward when arms hang naturally
  • Difficulty reaching behind back
  • Limited external rotation range of motion

Performance Impact: Increases impingement risk, reduces stroke efficiency, limits overhead reach

Weak External Rotators​

Muscles Affected: Infraspinatus, teres minor, posterior deltoid

Mechanism:

  • External rotation is only required during brief recovery phase
  • Internal rotators are 2-3x stronger than external rotators in swimmers
  • Insufficient direct training of external rotation
  • Fatigue of external rotators reduces dynamic shoulder stability

Manifestation:

  • Positive impingement signs
  • Difficulty controlling arm during recovery phase when fatigued
  • Shoulder instability sensation

Performance Impact: Primary contributor to swimmer's shoulder, reduces shoulder health longevity

Weak Scapular Stabilizers​

Muscles Affected: Lower trapezius, rhomboids, middle trapezius

Mechanism:

  • Swimming emphasizes scapular protraction (serratus anterior)
  • Limited scapular retraction demands in water
  • Upper trapezius becomes dominant over lower trapezius
  • Prolonged forward shoulder position inhibits middle trap activation

Manifestation:

  • Scapular winging at rest or during movement
  • Upper trap dominance causing neck tension
  • Inability to maintain retracted shoulder position on land
  • Poor scapular upward rotation

Performance Impact: Reduces force transfer from trunk to arm, increases impingement risk, causes neck pain

Forward Shoulder Posture​

Mechanism:

  • Combination of tight pecs/lats and weak rhomboids/lower traps
  • Prolonged streamlined position reinforces protracted posture
  • High training volume prevents adequate recovery of anterior structures

Manifestation:

  • Thoracic kyphosis (rounded upper back)
  • Forward head posture
  • Shoulders sit anterior to plumb line
  • Reduced thoracic extension mobility

Performance Impact: Reduces breathing efficiency on land, contributes to neck and upper back pain, limits overhead pressing strength

Hip Flexor Dominance​

Mechanism:

  • Flutter and dolphin kicks driven primarily by hip flexion
  • Prolonged horizontal position with hip flexion emphasis
  • Limited hip extension range needed in pool

Manifestation:

  • Tight hip flexors (iliopsoas, rectus femoris)
  • Anterior pelvic tilt
  • Compensatory lumbar extension

Performance Impact: Low back pain, reduced force transfer during land-based activities, poor running mechanics

Complementary Training​

External Rotation Exercises​

Purpose: Balance overdeveloped internal rotators, reduce injury risk

Key Exercises:

  • Band external rotations: 2-3 sets of 15-20 reps, light resistance
  • Side-lying external rotation: Controlled tempo, full range
  • Cuban press: Combines external rotation with overhead pressing
  • Scarecrow to press: Scapular retraction with external rotation

Programming: 3-4 times per week, can be performed daily as prehab

Technique Notes:

  • Keep elbow pinned to side or at 90-degree abduction
  • Emphasize control over weight
  • Full external rotation range without compensation

Horizontal Pulling (Rows)​

Purpose: Strengthen weak scapular retractors, improve posture

Key Exercises:

  • Chest-supported rows: Eliminates momentum, isolates rhomboids and middle traps
  • Face pulls: Emphasizes posterior deltoid and external rotation
  • Inverted rows: Bodyweight option, trains scapular retraction endurance
  • Single-arm dumbbell rows: Addresses asymmetries

Programming: 2-3 times per week, 3-4 sets of 8-15 reps

Technique Notes:

  • Initiate movement with scapular retraction
  • Focus on pulling shoulder blades together, not just bending elbows
  • Avoid upper trap dominance (don't shrug shoulders)

Lower Body Strength​

Purpose: Address relative lower body weakness, improve push-off power, enhance metabolic capacity

Key Exercises:

  • Squats (front and back): Build general lower body strength
  • Romanian deadlifts: Strengthen posterior chain, improve hip extension
  • Step-ups/lunges: Unilateral strength and stability
  • Hip thrusts: Glute development for powerful turns and starts

Programming: 2-3 times per week, moderate to heavy loads

Benefits:

  • Improved push-off power from walls
  • Better kick propulsion
  • Reduced injury risk when transitioning to land sports
  • Enhanced bone density (swimming is non-impact)

Hip Extension and Mobility​

Purpose: Counter hip flexor dominance, improve streamline position

Key Exercises:

  • Hip flexor stretches: Kneeling lunge stretch, couch stretch
  • Glute bridges: Activate underactive hip extensors
  • Supine hip flexor stretches: Passive stretching in supine position
  • 90/90 hip stretches: Improve internal and external rotation

Programming: Daily mobility work, 5-10 minutes

Technique Notes:

  • Avoid compensatory lumbar extension during hip flexor stretching
  • Focus on posterior pelvic tilt while stretching

Thoracic Extension Mobility​

Purpose: Counter kyphotic posture, improve breathing mechanics

Key Exercises:

  • Foam roller thoracic extensions: Over roller placed horizontally
  • Cat-cow progressions: Dynamic spinal mobility
  • Wall angels: Scapular control with thoracic extension
  • Quadruped thoracic rotations: Rotational mobility

Programming: Daily, especially pre-workout and pre-swim

Lower Trapezius Activation​

Purpose: Restore proper scapular upward rotation, reduce upper trap dominance

Key Exercises:

  • Prone Y-raises: Arms in Y position, thumbs up
  • Lower trap raises on incline bench: 30-45 degree angle
  • Scapular wall slides: Focus on depression and upward rotation
  • Overhead shrugs in Y position: Emphasize lower trap activation

Programming: 3-4 times per week, 2-3 sets of 12-20 reps, very light weight

Technique Notes:

  • Focus on scapular depression (down) and upward rotation
  • Avoid upper trap compensation
  • Quality over quantity - perfect form essential

Injury Patterns​

Swimmer's Shoulder (Impingement)

Mechanism: Repetitive overhead motion with internal rotation leads to subacromial space narrowing

Contributing Factors:

  • Weak external rotators and scapular stabilizers
  • Poor stroke mechanics (crossing midline, dropped elbow)
  • High training volume without adequate recovery
  • Muscle imbalances (strong internal rotators, weak external rotators)
  • Anterior shoulder capsule laxity

Symptoms:

  • Pain during overhead motions, especially during hand entry phase
  • Pain with internal rotation
  • Night pain when sleeping on affected side
  • Weakness during pull phase when fatigued

Prevention:

  • Regular external rotation and scapular strengthening
  • Video analysis of stroke technique
  • Periodized training with adequate recovery
  • Early intervention at first signs of pain

Treatment:

  • Reduce training volume temporarily
  • Physical therapy focusing on posterior shoulder strength
  • Improve stroke mechanics (higher elbow recovery, avoid crossover)
  • Address scapular dyskinesis
Rotator Cuff Tendinopathy

Mechanism: Overuse of rotator cuff muscles, particularly supraspinatus, from repetitive overhead motion

Contributing Factors:

  • High training volume (over 10,000m per day)
  • Insufficient recovery between sessions
  • Weak external rotators
  • Poor scapular control
  • Muscle fatigue leading to altered mechanics

Symptoms:

  • Gradual onset shoulder pain
  • Pain during mid-range of arm motion (painful arc)
  • Weakness with resisted external rotation or abduction
  • Pain that worsens with continued swimming

Prevention:

  • Progressive volume increases (no more than 10% per week)
  • Adequate rest days
  • Rotator cuff strengthening program
  • Proper warm-up before high-intensity sets

Treatment:

  • Relative rest (reduce volume and intensity)
  • Progressive loading program for rotator cuff
  • Address kinetic chain deficits
  • Consider stroke technique modifications
Low Back Pain

Mechanism: Excessive lumbar extension during swimming, particularly in butterfly and breaststroke

Contributing Factors:

  • Tight hip flexors causing anterior pelvic tilt
  • Weak core musculature
  • Poor body position (hips dropping)
  • Excessive lumbar extension to compensate for limited shoulder mobility
  • Inadequate hip extension range

Symptoms:

  • Pain during swimming, especially in extension-based strokes
  • Pain with prolonged standing or walking
  • Morning stiffness
  • Pain with land-based training

Prevention:

  • Core strengthening (anti-extension exercises)
  • Hip flexor stretching and glute activation
  • Streamline position drills
  • Avoid excessive arch in lower back during butterfly and breaststroke

Treatment:

  • Correct body position in water (engage core, avoid sag)
  • Address hip flexor tightness
  • Strengthen core and hip extensors
  • Modify stroke technique temporarily
Knee Pain (Breaststroker's Knee)

Mechanism: Valgus stress on knee during breaststroke whip kick

Contributing Factors:

  • Improper kick technique (knees wider than feet)
  • Weak hip abductors and external rotators
  • Excessive training volume in breaststroke
  • Medial collateral ligament (MCL) strain from repetitive valgus force

Symptoms:

  • Medial knee pain during and after breaststroke kick
  • Pain with knee valgus stress
  • Swelling along medial joint line
  • Pain with walking or stairs

Prevention:

  • Proper kick technique (knees in line with or narrower than feet)
  • Hip abductor and external rotator strengthening
  • Limit breaststroke volume if pain develops
  • Progressive volume increases

Treatment:

  • Temporary reduction or elimination of breaststroke
  • Strengthen hip abductors and glutes
  • Work with coach to correct kick mechanics
  • Consider cross-training with other strokes

Sources​

References

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  2. Sein ML, Walton J, Linklater J, et al. Shoulder pain in elite swimmers: primarily due to swim-volume-induced supraspinatus tendinopathy. Br J Sports Med. 2010;44(2):105-113.

  3. Beach ML, Whitney SL, Dickoff-Hoffman SA. Relationship of shoulder flexibility, strength, and endurance to shoulder pain in competitive swimmers. J Orthop Sports Phys Ther. 1992;16(6):262-268.

  4. Wanivenhaus F, Fox AJ, Chaudhury S, Rodeo SA. Epidemiology of injuries and prevention strategies in competitive swimmers. Sports Health. 2012;4(3):246-251.

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