Lunges are an excellent exercise to improve balance between the muscles in the lower body and avoid injury. Research shows that they also help develop sprint speed by providing the ideal ratio of muscle activation between two commonly unbalanced quad muscles. With an array of lunging options (front-foot elevated, forward, reverse, rear-foot elevated, jumping, static, and so on), it’s critical to train the right type to match your goals.

A study using junior soccer players compared training adaptations in a group that did walking lunges, a second group that did jumping lunges, and a control group. The walking lunge group improved hamstring strength by 35 percent after six weeks.

Researchers note this surprisingly large strength development was likely due to the young age of the participants. In comparison, the commonly used Nordic eccentric hamstring exercise has yielded strength increases of 11 percent in a previous study of older participants.

The jumping lunge group also increased hamstring strength but the increase was not statistically significant. Both groups improved 30-meter sprint speed: the jumping lunge group had the greatest increases in speed, getting 2 percent faster.

Another benefit of lunge training is that they develop structural balance in the quad and can decrease patellofemoral pain. A study from the University of Plymouth, England, found that static lunges (also called split squats) require the optimal ratio of muscle activation between the vastus medialis oblique and the vastus lateralis, the two principle muscles that stabilize the patella during knee extension.

Be aware of two things when considering which lunges to add to your training:

First, imbalances among the quad muscles can lead to the patella tracking incorrectly, which creates pain and degeneration of irreplaceable cartilage. Static lunges can be used for beginning trainees, to protect the knees, or as a warm up exercise for the more advanced walking and jumping lunges.

Second, the eccentric nature of dynamic lunges, especially jump lunges, will probably result in considerable delayed onset muscle soreness (DOMS) and fatigue after training. DOMS and strength loss typically indicate muscle damage and structural adaptations that require a longer time to heal than less stressful training modes.

References:
Jonhagen, S., Achermann, P., Saartok, Tonu. Forward Lunge: A Training Study of Eccentric Exercises of the Lower Limbs. Journal of Strength and Conditioning. 2009. 23(3), 972-978.

Irish, S., Millward, A., Wride, J., Haas, B., Shum, G. The Effect of Closed-Kinetic chain Exercises and Open-Kinetic Chain Exercise on the Muscle Activity of Vastus Medialis Oblique and Vastus Lateralis. Journal of Strength and Conditioning. 2010. 24(5), 1256-1262.