knee_extension PatternBeginnerPhase 1: Adaptation (Quad Isolation)
8. Leg Extension Machine
Isolates the quadriceps through knee extension, helping build single-joint thigh strength and knee stability under controlled resistance.
Primary MusclesQuadriceps (Rectus Femoris, Vastus Lateralis, Medialis)
Secondary MusclesKnee Extensor Tendons
EquipmentSeated Leg Extension Machine
Photorealistic Visual Guidance
B. Before You Start
Equipment Setup:
Select light weight pin (15-25 kg).
Seat Adjustment:
Adjust backrest so knees align with machine pivot axis.
Posture Alignment:
Back firmly against backrest pad.
Foot Placement:
Lower shin pad rests above foot ankles.
C. Starting Position
- Sit back with lower back resting against backrest.
- Place lower shins behind the padded roller bar.
- Grip side handles for upper body stability.
D. Movement Steps
- Exhale as you extend your legs smoothly upward until your thighs are fully contracted.
- Hold the top straight-leg position for a brief 1-second pause.
- Inhale as you slowly lower the roller pad back to the starting 90-degree position.
E-H. Breathing, Tempo & Prescriptions
Breathing
Exhale while lifting legs up. Inhale as legs lower down under control.
Tempo
2 seconds up, 1 second pause at top, 3 seconds lowering.
Range of Motion
From 90-degree knee bend up to full leg extension with soft knees.
Prescription
2 sets • 10-15 reps
RPE 5-6
I. What You Should Feel
Working Muscles
Deep burn across the front of your thighs (quadriceps).
Normal Effort
Isolated quad muscle fatigue.
Should NOT Feel
No sharp kneecap grinding or joint pain.
J. Common Mistakes
Kicking Weights Up Rapidly
Using explosive momentum to throw the weight pad upward.
💡 Coaching Cue: Lift smoothly using quad muscle strength only.
K-L. Safety Notes & Stop Conditions
Safety Notes
- Do not snap knees locked straight at the top.
Stop Immediately If
- Sharp kneecap pain
M-P. Variations, Alternatives & Progression
Easier Variation
Seated Leg Press with light weight
Machine Alternative
Leg Press Machine
Home Alternative
Seated Leg Straightening with bodyweight
Progression Rule
Increase weight pin gradually.