As stated before, one of the primary hip flexor muscles is the psoas major. This muscle plays a role in core stabilization (something that is needed during running, squatting, and sitting) due to its attachment site at the spine. If there is a lack of core stability or poor movement patterns during these tasks then the hip flexor can become overworked/tired/fatigued (think what happens when your co workers or teammates don’t do their job, you have to pick up the slack and work harder, bringing you more stress and fatigue). It is when the hip flexor becomes fatigued that the sensation of tightness sets in. This is because the hip flexor has to “work harder” to compensate for other muscles not doing their job.
The iliopsoas is another powerful hip flexor that begins in two distinct regions proximally. The iliacus has a broad origin, arising from the inner table of the iliac wing, the sacral alae, and the iliolumbar and sacroiliac ligaments. The psoas originates at the lumbar transverse processes, the intervertebral discs, and the adjacent bodies from T12 to L5, in addition to the tendinous arches between these points. Distally, the two large muscular bodies converge to become one distinct structure—the iliopsoas—and subsequently jointly insert at the lesser trochanter of the proximal femur. The nerve to the iliopsoas (i.e., the anterior division of L1 to L3) supplies the iliopsoas muscle.

In addition to adequate protein, you need more calories (your protein intake contributes to your total caloric intake, so these two go hand in hand). Use the following formula to calculate the number you need to take in daily to gain one pound a week, and break down your diet using the macro guidelines listed above. (Give yourself two weeks for results to show up on the scale. If you haven't gained by then, increase your calories by 500 a day.)
The high levels of muscle growth and repair achieved by bodybuilders require a specialized diet. Generally speaking, bodybuilders require more calories than the average person of the same weight to provide the protein and energy requirements needed to support their training and increase muscle mass. In preparation of a contest, a sub-maintenance level of food energy is combined with cardiovascular exercise to lose body fat. Proteins, carbohydrates and fats are the three major macronutrients that the human body needs in order to build muscle.[24] The ratios of calories from carbohydrates, proteins, and fats vary depending on the goals of the bodybuilder.[25]
Eat healthy fats. That's right—not only does it make food taste good, fat is good for you, as long as you are eating the right kinds and amounts of fat! Saturated fats—the fat you'll find in a stick of butter, a bag of chips, or bacon—should be limited to about 20g or less. That's the bad news. The good news is that unsaturated fats are actually beneficial, even necessary. Fat is necessary for the proper distribution of vitamins A, D, E, and K, helps promote better eyesight, and healthy skin. Fats are also important for the synthesis of hormones, so maintaining an adequate intake of them will speed up muscle-building and recovery.
Lie on your back with knees bent and feet flat on the floor. Lift your hips to come into a bridge position. Lift your left leg off the ground and extend it in front of you, keeping your pelvis level. Inhale as you slowly lower your hips toward the ground. Exhale as you drive your right heel into the ground and lift your hips. Do 10-12 reps. Switch sides.
That pump is tangible, real-time biofeedback to let you know that blood is flowing to your muscle cells, beginning a chain of events that stimulates protein synthesis. Maybe that'’s why it's easy to overlook how important good nutrition is in the mass-building equation. When you choose to eat, say, chicken instead of ice cream, there'’s no immediate muscle gratification -- no pump to keep you motivated.
You may hear a clicking noise when you move your hip, but that sound is not necessarily a hip flexor issue. Siegrist says the clicking isn't generally the hip flexor alone and often comes from a moving part, like the joint. "Maybe there is a loose body in the joint or loose cartilage at the edge of the hip joint that is mechanically getting irritated,” she says.

Consuming sufficient high-quality protein is essential for building muscle. Current recommendations are to consume a minimum of 0.8g of protein for each kg of body weight, however, this is really only applicable to the average sedentary individual. Current evidence shows that to support muscle development, protein intake is the key, therefore the recommended 0.8g per kg should be increased to 1.5-2.0g of protein per kg of body weight. For an 80 kg individual, that would equate to 120-160 grams of protein per day.
Having a strong butt will get you far—literally. Our glutes are responsible for powering us through everything from long runs to tough strength workouts to a simple jaunt up a flight of stairs. Strong glutes that can take on the brunt of the work can help us avoid overcompensating with smaller muscles during lower-body exercises. Plus, beyond just helping us move, the glutes play an important role in "stabilizing our entire lumbo-pelvic-hip complex," says Cori Lefkowith, NASM-certified personal trainer and owner of Redefining Strength in Costa Mesa, California. That translates to better form, more efficient movement, and a reduced risk of straining your lower back and hips.
Firstly, let’s establish where your glutes are and what they actually refer to! Your ‘glutes’ — or your gluteal muscles, as they are more formally known — refer to the muscles in your butt. Specifically, there are three major muscles in this area: your gluteus maximus (the main, large muscle that shapes your backside), your gluteus medius and your gluteus minimus (two smaller muscles that assist the gluteus maximus in moving your body).