Muscles of the core are classified as either “Global” or “Local” muscles. The global core muscles are more superficial, larger and stronger and have attachment sites at the hip (e.g., abdominals, obliques, erector spinae). Local muscles are intrinsic (deeper), smaller and typically attach directly to the spine and contribute to segmental stability. Coordination of both the global and local muscles of the core is fundamental in reducing injury potential and maximizing performance.
Most coaches have a very limited understanding of the function of the core muscles and how they contribute to athleticism. Training of the core musculature at workouts or as part of a practice typically involves conventional trunk flexion exercises like crunches and sit-ups. Whether repeated trunk flexion exercises are contraindicated or not due to potential injury risk to the intervertebral discs is a hot topic in the performance field and is beyond the scope of today’s post. Instead, we will take a look at how the core may be better trained to contribute to performance improvements in athletes.
An interesting new study was just published in the International Journal of Sports Physical Therapy compared the effectiveness of conventional core training (sit-ups, back extension type movements) verses core stability training on indices of balance and athletic performance in a team of young soccer players. This study had three components;
1) Pre-testing: The testing battery included static balance (blinded balancing on one foot), dynamic balance (blinded balancing on one foot with reaching in various directions with other foot), agility, sprint time, vertical jump and endurance (12 minute run).
2) 12 Week Training Intervention: This involved 3 core training sessions per week following soccer practice. One group (n=10) performed conventional core exercises (flexion and extension of the core) while the other group (n=9) performed core stability exercises (various planks, bird dogs and hip bridges. Four exercises were performed each session with intensity and or duration progressing over the course of the 12 week period.
3) Post-Testing: The athletes underwent the same testing battery performed at pre-testing to determine any changes in performance.
The researchers reported that apart from vertical jump and sprint times (which increased significantly in both groups), significant improvements in each of the other parameters were only observed in the core stability training group.
The evidence is continuing to mount, favoring core stability training in addition to, or instead of conventional core exercises. Athletic actions commonly performed in sports (e.g., jumping and landing mechanics, etc.) require coordination and co-contraction of the core muscles to optimally transfer forces and stabilize the lumbar spine. Instead of having your athletes perform countless crunches and sit-ups, consider various core stability exercises such as timed forearm and side planks to have a better transfer effect to performance.
Reference:
Imai, A., Kaneoka, K., Okubo, Y., & Shiraki, H. (2014). Effects of two types of trunk exercises on balance and athletic performance in youth soccer players. International Journal of Sports Physical Therapy, 9(1), 47.
