A strong core is important for all athletes. Endurance athletes benefit from a strong core to maintain form and prevent injury due to fatigue. There are many great core exercises. This workout is a good general core strengthening routine. Do each exercise once to fatigue.
Start face down supported on toes and elbows. Elbows should be directly under the shoulders bent 90 degrees. Shoulders, hips and ankles are inline. To increase difficultly alternate lifting one foot and then the other off the ground and hold.
Sit supported on sit bones. Lift feet approximately 30cm with straight legs and balance. Use hands for support as needed. Kick feet similar to a freestyle flutter kick in short, quick kicks. To increase difficulty cross arms at chest.
Start on all fours with hands directly under shoulders and knees directly under hips. Extend one are and the alternate leg out straight to horizontal and return to the start position. Alternate sides after each rep.
Start laying on back with legs bent 90 degrees and feet hip distance apart. Raise hips while contracting abdominals until shoulders, hips and knees and in line. Push hips upwards as far as possible then return to start position. To add difficulty alternate straightening one leg and then the other with thighs parallel.
Lay on back, legs parallel and arms at sides. Pull hip and shoulder together on the same side while keeping legs together. Alternate sides.
Start supported on one elbow with the elbow directly under the shoulder, feet stacked and shoulders, hips and ankles in line. To add difficulty lift the top leg, and/or add rotation by reaching under and behind with the top arm.
Stand upright, feet shoulder width apart. Lean forward and touch the ground while lifting the opposite foot until the leg is parallel to the ground. Alternate sides. After 10 reps each side switch to lifting the same side leg.