This article originally appeared on Triathlete

It’s normal for triathletes to focus on the obvious muscle groups like the pecs and shoulders for swimming, the glutes and quads for cycling, and the hamstrings and calves for running. But what links all these muscle groups together? The back and core! If you want to maximize your triathlon performance and get the most out of your training, it’s imperative you’re operating from a well-conditioned back and core. And one of the best ways to make sure your back and core is in tip-top shape is with regular stretching and flexibility training using the best back stretches for triathletes.

Triathlon stretches are one of the most under-utilized techniques for improving athletic performance, preventing sports injury and properly rehabilitating sprain and strain injury. Don't make the mistake of thinking that something as simple as stretching won't be effective. Below are seven of the best back stretches for triathlon; obviously there are a lot more, but these are a great place to start. Please make special note of the instructions with each stretch, and if you currently have any chronic or recurring muscle or joint pain, please take extra care when performing the stretches below (or consult with your physician or physical therapist before performing any of the following stretches).

RELATED: 6 Simple Poses for Stretching Sore Tri Muscles

Back Stretches for Triathletes

Instructions: Slowly move into the stretch position until you feel a tension of about 6 or 7 out of 10. If you feel pain or discomfort you've pushed the stretch too far; back out of the stretch immediately. Hold the stretch position for 20 to 30 seconds while relaxing and breathing deeply. Come out of the stretch carefully and perform the stretch on the opposite side if necessary. Repeat 2 or 3 times.

Lying Double Knee-to-chest Stretch

Lie on your back and use your hands to bring both knees into your chest.

Lying Leg Cross-over Stretch

Lie on your back and cross one leg over the other. Keep your arms out to the side and both legs straight. Let your back and hips rotate with your leg.

Sitting Side Reach Stretch

Sit with one leg straight out to the side and your toes pointing upwards. Then bring your other foot up to your knee and let your head fall forward. Reach towards the outside of your toes with both hands.

Rotating Stomach Stretch

Lie face down and bring your hands close to your shoulders. Keep your hips on the ground, look forward and rise up by straightening your arms. Then slowly bend one arm and rotate that shoulder towards the ground.

Sitting Neck Flexion Stretch

While sitting on a chair, cross your arms and hold onto the chair between your legs. Let your head fall forward and then lean backwards.

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Sitting Lateral Side Stretch

Sit on a chair with your feet flat on the ground, then slowly bend to the left or right while reaching towards the ground. Do not bend forward.

Standing Leg-up Toe-in Hamstring Stretch

Technically, the hamstrings aren’t part of the back or core, but tight hamstrings can put a lot of stress on the lower back, so I’ve included this stretch help take some of the pressure of your lower back. Stand upright and raise one leg on to an object. Keep that leg straight and point your toes upwards. Then point the toes of your other foot inward and lean forward while keeping your back straight.

RELATED: How to Stretch Your Hamstrings Safely

Brad Walker, also known as “The Stretch Coach,” is a health Science graduate of the University of New England and has postgraduate accreditations in athletics, swimming, and triathlon coaching. He has written more books and articles on stretching and flexibility than any other author; his titles include the Ultimate Guide to Stretching, the Anatomy of Stretching and the Anatomy of Sports Injuries.

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