The Prone Plank
The prone plank exercise has become a common component for various types of core stability programs. Static holds in general have been used within exercise routines for fitness, group exercise and even athletic conditioning. Although very popular, the effectiveness of plank exercises is in question as little transfer into dynamic activities has been clearly demonstrated. Based on a review of literature, there is minimal evidence which supports the claim that static core stability training transfers into improved performance. In a recent study published in the Journal of Bodyworks and Movement Therapy (2011), investigators compared the effects of a 6-week unstable static versus unstable dynamic core training program on field-based fitness tests. The treatment groups performed two 45 min exercise sessions per week for six weeks. Seven performance tests, consisting of three core (plank; double leg lowering; back extensions), one static (standing stork) and three dynamic (overhead medicine ball throw; vertical jump; 20 m sprint), were administered pre- and post training. Although the specific treatments demonstrated improvements in the activities, neither training group demonstrated improvement in the dynamic field-based tests. Findings indicate that both types of training improved specific measures of core stability but did not transfer into any explicit sport-related skill.
According to a 2010 study published in the Journal of Strength and Conditioning Research, Keogh et al suggests core stability training may only lead to significant improvements in functional dynamic performance if the postures, mode, and velocity of contraction performed in training are similar to the competitive tasks performed. Findings go on to support task-specific training for improved core dynamics over static activities that have no transfer or duplicity in tasks of free living. Planks and related isometrics may be used to instruct proper core activation and posture appropriateness, but seem to do little else for human performance. This is particularly true if the positions use compensatory actions to maintain the static holds. The most common error during the performance of trunk stability exercises is the use of the dominant muscles in the hip and back. It is very common to see a sagging of the back during a plank as exercisers oftentimes rely on back extensor musculature to hold the position. This is usually examined in conjunction with a protracted scapular position due to pectoralis major dominance. Another common error (or means of cheating) is the maintenance of a high hip position so that the exerciser can rely on the hip flexors for equilibrium. If the only value of plank exercises is to elicit activation in the core musculature, then it should be used accordingly. The following cues will help ensure the plank exercise is performed with improved efficiency.
- If the scapulas are protracted (winged scapula), cue the exerciser to elevate the chest by extending the thoracic spine.
- If the back sags, cue the draw-in action to maintain a straight back.
- If the hips, rise cue a contraction of the gluteals musculature (squeeze the glutes) to unhook the hip flexors through reciprocal inhibition.
Utilization of the previous teaching cues may assist in better prone plank posture and serve as an instructional foundation for techniques of improved stability when performing more dynamic activities. Once the plank has been mastered, it can be progressively altered to be more dynamic in nature. See the NCSF YouTube videos for ideas related to this such as the Athlete’s Plank exercise.