I've noticed most trainers have there philosophy that shapes the way they program their gym work. Some guys are into kettle bells, others love to do super heavy squats and deadlifts. Others have drank the P90X or Crossfit koolaid. I have subscribed to the idea of single leg training. Many of the top strength coaches believe and use this method in training their pro athletes.
To me, single leg training makes the most sense for bmx training and most sports. Training should be specific to what you're training for. When you pedal you drive the front foot down while your back foot un-weights on the upstroke. At no point in your pedal stroke is both legs driving down simultaneously (hopefully). We walk, run, and pedal one leg at a time; why shouldn't we train that way?
Single leg training also allows you to lower the overall load on your spine during squats, but impose the same load on the leg being trained as bi-lateral training. This can be good for people with back problems and prevention of future problems from too much spinal compression. I like the core demand and balance that lifting off of one leg gives you (two major qualities of a good athlete). Single leg work will also help minimize muscle imbalances that we have developed from doing thousands of gate starts with our dominant leg forward. Another thing I've noticed while doing single leg squats, S. L. dead lifts, and S.L. split squats is the tempo at which you perform these is much safer than the tempo than when you're on two feet. Try doing a single leg squat or dead lift quickly and you will probably fall over as you lower too quickly. You will do this a few times and quickly figure out the eccentric part of single leg work needs to be done at a slower pace, but the concentric portion of the lift can be just as explosive as bi-lateral squats.
I'm not telling anyone to give up bi-lateral training totally, but give some single leg work a try. Here is a good article on the virtues of including single leg training to your lower body training written by a very smart strength coach.
Video here --->share