Analysis By Dr Paul Batman. P.hD
- Place a barbell across the top of your shoulders just below the neck
- Stand upright with your feet approximately shoulder distance apart
- Keep your eyes focused straight ahead and your abdominals and spinal extensors contracted
- Begin the exercise by taking a smooth step forward with your right leg, being careful not to overstride
- Your right foot should be placed straight ahead, far enough to allow approximately 90 degrees of flexion of your right knee joint
- Slowly lower your hips until your right thigh is parallel to the ground. Keep your back straight at all times
- Your right knee should be over your right foot
- Your left leg should be bent and positioned behind your body in astride position
- After a short pause push off the balls of your right foot and slide your foot back to the original starting position
- Repeat the movement with your left leg forward
Joint Action Contraction Muscle Group
Hip joint Extension Concentric Hip Joint Extensors
Knee Joint Extension Concentric Knee Joint Extensors
Ankle Joint Plantar Flexion Concentric Ankle Joint Plantar Flexors
In the down phase of the exercise the weight is lowered slowly with gravity. The same muscles that concentrically contracted to lift the weight are those that are eccentrically contracting to lower the weight.
General Kinesiological Analysis
In up phase of a lunge, the lead leg is extended at the hip joint, knee joint and plantar flexed at the ankle joint. Extension of the hip joint is caused by the concentric contraction of the gluteus maximus, semimembranosus, semitendinosus and the biceps femoris. Extension of the knee joint is caused by the concentric contraction of the vastus medialis, vastus lateralis, vastus intermedius and the rectus femoris. Plantar flexion of the ankle joint is caused by the concentric contraction of the gastrocnemius, soleus, tibialis posterior, flexor digitorum longus, flexor hallucis longus, peroneus longus and the peroneus brevis.
Advanced Kinesiological Analysis
The barbell lunge is essentially a one legged squat. The lead leg undergoes the greatest muscle activity, while the rear leg is used to maintain balance.
The prime movers of the hip joint in the lead leg during a barbell lunge, is the gluteus maximus, semimembranosus, semitendinosus and the biceps femoris. The prime movers at the knee joint are the vastus medialis, vastus lateralis, vastus intermedius and the rectus femoris. The prime movers at the ankle joint are the gastrocnemius and the soleus. The assistant movers are the tibialis posterior, flexor digitorum longus, flexor hallucis longus, peroneus longus and the peroneus brevis.
Some studies have reported the increased recruitment of the adductor magnus and adductor brevis in hip joint movements in the lunge. This is possibly due to the increased fixation and stabilization required to balance the barbell at the time the hip and knee joint extend.
Due to the astride position of the legs in the barbell lunge there is a significant increase in the degree of stabilization required to maintain balance. While the base of support of the astride legs is adequate, the barbell resting on the shoulders produces a counter current effect. This is not dissimilar to someone walking a tightrope with arms to the side of the body for balance. Lunges require a significant contribution of the abdominals and the spinal extensors to stabilize the trunk in order to prevent lateral flexion and an unbalanced state. Clients learning to lunge for the first time are often more suited to performing the exercise on a smith machine until the required motor pattern has been developed.
The stabilization of the lead leg is also affected by the neutralization of the semimembranosus and the semitendinosus causing medial rotation of the hip joint, while the gluteus maximus and the biceps femoris causing lateral rotation of the hip joint at the same time they are all contracting together to cause hip joint extension. The same can be said of the ankle joint. When the full weight of the barbell is borne over the lead foot, the tibialis posterior, the flexor digitorum longus and the flexor hallucis longus will attempt to cause inversion of the ankle joint, while the peroneus longus and the peroneus brevis will attempt to cause inversion of the ankle joint, while both sets of muscles contract together to cause plantar flexion of the ankle joint.
A variation to the barbell lunge is the reverse lunge performed on a smith machine. In this exercise, the client is positioned under the bar in a smith machine. The client will stand initially with both feet shoulder distance apart. From this position the client steps forward with the right foot. From this starting position, the client will then swing their left leg forward past the trunk to a hip flexion position. The client will pause in this position and then swing the leg backward to the original starting position, allowing them to assume a lunge position. The client will lower their body weight in the lunge position and then proceed to repeat the same exercise again.