Cross Training for Multi-Sport Athletes: Start with a Strong Core!

When most people think of “triathletes,” visions of swimming, biking and running immediately come to mind. Whether you compete in a local sprint triathlon, or perhaps undertake the challenge of an IronMan®, a stable core is necessary to finish strong and prevent injury.

While it’s true an athlete must spend the applicable time dedicated to each individual sport, it is important to realize what a strong role the core plays in each discipline. The core is the coupling link between the upper and the lower body. It also functions as a stabilizer. Perhaps you’ve heard of the core referred to as the “power center,” a place where power for movement is generated and distributed throughout the body during activity. In addition to generating powerful movements, such as those used during swimming and running, an athlete must also remain stable, maintaining “dynamic balance” during the bike portion of the race. Another thing to consider is that triathletes are often spending numerous hours moving in the sagittal plane, which can cause muscle imbalances and tightness in certain joint areas such as the hip flexors.

The good news is that there are two products a multi-sport athlete can train with to focus on core strength, mobility, stability and dynamic balance: The BOSU® Balance Trainer and the BOSU® Ballast® Ball.

Let’s take a look at a basic exercise called "The Swimmer" performed on The BOSU® Balance Trainer in a prone, or face down position. This exercise mimics the motion of swimming. The core is acting as a stabilizer as the arms and legs move in opposition to one another. Being elevated 8 - 10 inches off the ground allows for increased range of motion as well as the dome provides a padded surface to lie on. Try 8 - 15 repetitions of alternating arm and leg raises, then progress the movement to fluttering arm and leg motion to replicate a swimming motion. Aim for 2 - 3 sets.


Another important exercise to perform is one that involves hip extension. Think of the body position an athlete is in for an extended period of time on the bike. The hip flexors need an exercise that “opens” them up, to combat the time spent in hip flexion. This Hip Extension exercise that uses the Balance Trainer and the Ballast® Ball is excellent for working on both opening the hips and strengthening the spinal extensors, as well as challenging dynamic balance. Again, 8 - 15 repetitions with the hands on the floor is an excellent place to start, and for added challenge try an alternating arm drive to decrease stability and fire up the posterior muscles of the body. Aim for 2 - 3 sets.


The third exercise that is important not only for multi-sport athletes but also people in general is back extension. Weak lumbar or lower back muscles are way too common in today’s society. Whether you sit on a bike seat or an office chair, this exercise can help strengthen an area that is often weak. The BOSU® Ballast® Ball helps by creating a surface that is comfortable to drape over while performing spinal extension. By adding a slight rotation at the top of the move, this exercise becomes even more of a bonus. If back muscles are weak or tight, try the movement with feet wide (or knees on the floor) and hands on ball. Work through a gentle range of motion that your back and spine allow. Adding rotation at the top of the movement is complex progression and should be completed only if proper form can be maintained. Perform 8 - 15 repetitions and aim for 2 - 3 sets.


Multi-sport athletes often complain of not having enough time to cross train due to the nature of trying to tackle more than one sport at the same time. However, if you allow yourself at least 1 - 2 days per week to cross train and work on core muscles and flexibility, you will be able to swim, bike and run to your fullest potential!

Pam Benchley is a Hedstrom Fitness Master Trainer for BOSU®, Kamagon® and Surge®, and a provider of many other workshops including Stages® Indoor Cycling, balance training, and functional/active aging training. Pam currently serves on the faculty at the State University of New York at Fredonia and is a competitive triathlete.

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