The nature of our fast-paced Western world is that we want everything bigger and better, and we want it yesterday. Demand for time efficient activities — with more dramatic results — permeates into every area of our lives, particularly with regard to physical activity. When choosing strategies for any exercise program, it is important to consider how much bang for your buck will be delivered by your decision.
It is widely acknowledged that core conditioning is an essential element of any training regime. The American College of Sports Medicine1 and the United States Department of Health and Human Services2 recommend that healthy adults participate in core exercises twice weekly as a means to improve stability, reduce injury and maintain mobility. Of course, there are a myriad of exercises we can perform to target the primary core muscles, but until recently, no study had ever been devoted to the exploration of which exercises, isolation or integration, provoke the greater muscle activation.
We define isolation exercises as simple, localized movements that target only one muscle group (e.g., the crunch) and integration as complex, multi-joint exercises that combine trunk muscle activation with contractions of the limb muscles (e.g., the hover or plank). An understanding of the difference between the strategies would, it was reasoned, optimize functional and performance gains, thereby enabling sports and medical professionals to prescribe the most favorable exercises to aid sports performance, rehabilitation and general fitness.
A study published this year, in association with Pennsylvania State University, hypothesized that isolation-type exercises would elicit the greater muscle activation when compared to integration-style exercises. A total of 20 healthy college students (10 male, 10 female) were recruited to perform 16 isolation and integration exercises to measure the muscle response. EMG electrodes were placed over the appropriate points of six muscles. The movements the students were required to perform included an isolated crunch versus the integrated hover with hand reach and an isolated oblique twist versus the integrated side hover.
The results were dramatic and demonstrated clearly that integration exercises elicit the greatest muscular activation. The hypothesis that isolation exercises would promote the larger muscular reaction was completely turned on its head. The study found that abdominal and lumbar muscle activity was greatest when these muscles worked together in conjunction with the limb muscles. When comparing the integrated movement of a hover with hand reach to the traditional isolated crunch, there was a 27 percent increase in rectus abdominis and external oblique activity for the hover. When erector spinae activity was measured for both an isolation double arm trunk extension and an integration horse stance pointer, the overall activity was 38 percent greater during the integration task. In essence, incorporating activity at the shoulder and hip resulted in the need for greater activation of the primary abdominal and back muscles, as well as activating the distal limb musculature.
It is perhaps no surprise that integration exercises are superior at eliciting the greater muscle activity. Integrated movements are more aligned with the way we use our trunk for everyday activities, thereby delivering a more functional benefit. This functionality is sometimes referred to as Reactive Core Training: a situation is created in which the core responds automatically, rather than as the result of a voluntary contraction.
The study found that for quality, time-efficient training, integrated exercises should be incorporated into a core-strengthening program to maximize strength, improve endurance, enhance stability, reduce injury and maintain mobility.
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References:
1. American College of Sports Medicine. ACSM’s Guidelines for Exercise Testing and Prescription (8th ed.). Thompson, WR, ed. Philadelphia, PA: Lippincott, Williams & Wilkins, 2010.
2. US Department of Health and Human Services. 2008 Physical Activity Guidelines for Americans. Services, H.a.H, ed. Washington, DC: U.S. Department of Health and Human Services, 2008.
Les Mills International is the creator of 13 global group training programs, including CXWORX™, a core training program that was selected by Consumer Reports as one of their top exercise programs for 2014. For more information about Les Mills or to find a CXWORX™ class near you, visit www.lesmills.com.
