LEG or KNEE EXTENSIONS – RESEARCH
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STRENGTH RESEARCH
KNEE EXTENSION TORQUE & KNEE FLEXION TORQUE
– Ankle Plantar Flexed or Dorsi Flexed
Effect of ankle position on isokinetic knee extensor and flexor strength gains – 2016 – Kim
Procedure
– trained isokinetically and concentrically in knee extension and flexion 4x/week for 3 weeks
– dorsiflexion is toes up; plantarflexion is toes pointed
Strength Gains
– difference was significant at slower speed
Knee Extension – 60 degrees/second: dorsiflexion 30% . plantarflexion 2%
Knee Extension – 180 degrees/second: dorsiflexion 22% . plantarflexion 18%
Knee Flexion – 60 degrees/second: dorsiflexion 66% . plantarflexion 22%
Knee Flexion – 180 degrees/second: dorsiflexion 42% . plantarflexion 35%
EMG STUDIES
RECTUS FEMORIS
– Knee Extension & Hip Flexion
Task-dependent spatial distribution of neural activation pattern in human rectus femoris muscle – 2012 – Watanabe
Procedure
– tested the rectus femoris as a knee extensor and as a hip flexor
– the rectus femoris (RF) muscle is innervated by two nerve branches attached at proximal and distal parts of the muscle
– tested isometric knee extension and hip flexion, at 20%, 40%, 60% and 80% of maximal voluntary contraction (MVC)
Results
Rectus Femoris as a Knee Extensor @80% MVIC: distal 100% . middle 98% . proximal 96%
Rectus Femoris as a Hip Flexor @80% MVIC: proximal 75% . middle 55% . distal 42%
RECTUS FEMORIS & VASTUS LATERALIS
– Knee Extension vs. Squat vs. Step-up vs. Lunge
Muscle activation during lower body resistance training – 2009 – Ebben
Procedure
– 20 athletes and recreationally active college students
Results – MVIC
Rectus Femoris: leg extension 90% . lunge 80% . squat 80% . stepup 65%
Vastus Lateralis: lunge 90% . squat 90% . stepup 80% . leg extension 80%
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RECTUS FEMORIS, VASTUS MEDIALIS, LATERALIS & INTERMEDIUS
– Knee Extension
Single-joint eccentric knee extension preferentially trains rectus femoris within the quadriceps muscles – 2018 – Maeo
Procedure
– isokinetic maximal eccentric contractions of knee extensors in one leg (ECC-leg)
– isokinetic maximal concentric contractions of knee extensors in the other (CON-leg)
Results
– Muscle volume significantly increased in all muscles in ECC-leg only, with a greater degree for RF (+7.3%) than the vasti (2.9%-3.7%)
Eccentric Knee Extension: Rectus Femoris 70% . V-Intermedius 45% . V-Medialis 35% . V-Lateralis 30%
GLUTEUS MAXIMUS, RECTUS FEMORIS, VASTUS LATERALIS, VASTUS MEDIALIS
– Standing Kickback vs. Leg Press vs. Knee Extension
EMG Comparison of 5 Lower-Limb Muscles between Single- and Multi-Joint Exercises among Trained Men – 2021
– Nicolay Stien, Atle Hole Saeterbakken, and Vidar Andersen
Procedure
– 15 resistance-trained men
Exercises
1. Leg Press: starting position 90° knee flexion; 60° hip flexion; extended knee to 180° and hip joints 150°
2. Knee Extension: started at 90° knee flexion; performed to a full extension 180°
3. Kickback: standing; 90° angle in the hip joint; knee semi-extended 170°; concentric 180° in the hip joint
Results
Gluteus Maximus: leg press 90 . kickback 80
Rectus Femoris: knee extension 95 . leg press 70
Vastus Lateralis: leg press 105 . knee extension 90
Vastus Medialis: leg press 95 . knee extension 80
+ Biceps Femoris: kickback 105 . leg press 30
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