In case you weren't aware, your butt is pretty amazing. It helps your body stay upright, enables you to power through workouts, and looks fantastic when squeezed into a pair of skinny jeans, just sayin'. That's why it's so important for you to know how to get the most out of your glutes, the muscles in your posterior. Read on for all the crazy details.
Overtraining occurs when a bodybuilder has trained to the point where his workload exceeds his recovery capacity. There are many reasons why overtraining occurs, including lack of adequate nutrition, lack of recovery time between workouts, insufficient sleep, and training at a high intensity for too long (a lack of splitting apart workouts). Training at a high intensity too frequently also stimulates the central nervous system (CNS) and can result in a hyperadrenergic state that interferes with sleep patterns.[51] To avoid overtraining, intense frequent training must be met with at least an equal amount of purposeful recovery. Timely provision of carbohydrates, proteins, and various micronutrients such as vitamins, minerals, phytochemicals, even nutritional supplements are acutely critical. A mental disorder informally called “bigorexia” (by analogy with anorexia) may be held accountable of some people overtraining. Sufferers feel as if they are never big enough or muscular enough, which forces them to overtrain in order to try and reach their goal physique.[52]
Located deep in the front of the hip and connecting the leg, pelvis, and abdomen, the hip flexors— surprise, surprise— flex the hip. But despite being some of the most powerful muscles in our bodies (with a clearly important role), it’s easy to neglect our poor hip flexors— often without even knowing it. It turns out just working at a desk all day (guilty!) can really weaken hip flexors since they tend to shorten up while in a seated position. This tightness disrupts good posture and is a common cause of lower back pain. Weakened hip flexors can also increase the risk of foot, ankle, and knee injuries (especially among runners) Hip muscle weakness and overuse injuries in recreational runners. Niemuth, P.E., Johnson, R.J., Myers, M.J., et al. Rocky Mountain University of Health Professions, Provo, VT. Clinical Journal of Sport Medicine, 2005 Jan; 15 (1): 14-21.. So be sure to get up, stand up every hour or so! And giving the hip flexors some extra attention is not just about injury prevention. Adding power to workouts, working toward greater flexibility, and getting speedier while running is also, as they say, all in the hips The effect of walking speed on muscle function and mechanical energetics. Neptune, R.R., Sasaki, K., and Kautz, S.A. Department of Mechanical Engineering, The University of Texas, Austin, TX. Gait & Posture, 2008 Jul; 28 (1): 135-43..
The hip flexors are a group of muscles in the front of the hip that act to lift the knee and bring the thigh towards the abdomen. The major muscles making up the hip flexors that we will focus on are the iliacus and the psoas, or the iliopsoas and the rectus femoris. The rectus femoris  is a “two joint muscle” because it crosses both the hip and knee joints. As a group, the hip flexors have attachments on the lumbar spine, the pelvis, and the femur. In addition to their major function of flexing the hip, their attachment on the spine makes them an important part of the core muscles and spinal stabilizers.
Note that this recommendation is for total weekly volume, which means it would need to be divided up based on how many times you’re training each muscle group per week. So, for example, someone training everything twice per week would do 30-70 reps for each bigger muscle group in each of those workouts, and 15-35 reps for each smaller muscle group in each of those workouts.