Who a strong core has, has a strong practice. Strong core is more than exercising with crunches and sit ups or doing #plankchallenge alone. Having a strong core is having a strong practice. Whatever your sport is, Yoga, Strength Training, Crossfit or Running you will require to have strength in your core muscles. Core is the midsection of your body, that includes abdominals, back muscles, and all muscles involved from the thorax to the pelvis. You get your core strong when you perform deadlifts, pull-ups, squats and presses.
CORE MUSCLES:
Transversus abdominis, multifidus, internal and external obliques, rectus abdominis, erector spinae, longissimus thoracis, and the diaphragm, latissimus dorsi, gluteus maximus, and trapezius.-Wikipedia

BENEFITS OF MOUNTAIN CLIMBER
Mountain climbers is a full body workout, burns your fat, builds your abs and strengthens your shoulders, builds explosiveness.
MUSCLES INVOLVED:
Deltoids, biceps, triceps, pectoralis major, obliques, rectus abdominals, lower trapezius, latissimus dorsi, quadriceps, hamstrings, hip adductors, hip abductors.

Sport BH: similar H & M, Top: similar Oysho, Leggings: Nike Sneakers: Oysho Photos credit: Markus Hass
BENEFITS OF BABY SIDE CROW
Baby side crow or Parsva Bakasana strengthens the arms, wrists, shoulders, abdominal muscles, and spine. the upper back and groins. Improves flexibility throughout the spine and lower back.
MUSCLES INVOLVED:
Deltoids, wrists, biceps, triceps, pectoralis major, serratus anterior, rectus abdominals, trapezius, iliopsoas.
BENEFITS OF SIDE PLANK ELBOW LEG RAISE
Side Plank elbow leg raise strengthens your core stability, strengthens your buttocks, improves your breathing, strengthens your legs and arms.
MUSCLES INVOLVED:
Deltoids, biceps, triceps, pectoralis major, obliques, rectus abdominals, lower trapezius, latissimus dorsi, quadriceps, hamstrings, hip adductors, hip abductors.
STRONG CORE, STRONG PRACTICE
To be honest I do not have core days in my training program, what I do is to incorporate 3-4 drill as finishers of my training day if I have extra time. Normally I use a core routine as a warm up and that involves multiple joint movements and includes the wrists and shoulders if I have a upper body training day or ankles, knees and hips for my lower body day.
Yoga balances and primal moves like locomotion will get your core strong. Add them to your monthly training program and have fun with them. Here is a quick fun Core Circuit Workout for you with this mix of drill and yoga pose to strengthen your body muscles that stabilizes the whole body for an optimum performance in life and fitness.