The hardest day(s) for me is when I'm really not in the mood for any serious training. Dragging my arse to the gym, I'll try to gather a whole new mindset to working out. If I start extra light and slow I'll usually get more serious towards working out after about 10 minutes or so. Or I'll try something completly different than what I had been doing in a workout. Variety can spice up things, from time to time, if only to relieve the boredom factor.
Why workout one leg at a time? Better balanced leg development and strength, for one. Most people will have one side of their body larger and stronger than the other: pecs, arms, delts, etc. . Exercising each side, on a separate bases, can influence a more equal muscle match for both sides.
I'll include step-up's, which are not to be confused with a one legged squat. Step-ups are where you place a foot on a bench, box, etc in front of you and just step up onto the bench. A lot of olympic lifters include step-up in their training cycle. One legged squats usually have one leg, on a bench, along side the body as you push the body up from that position. Step-ups tend to influence the hams & glute, as do the regular lunges, but with a better recuitment/stretch of those muscles. The Bulgarian squat is one of the few leg movement that calls for the knee/toe's to be pretty much in alinement during the exercise. Good Luck.
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