Chances are that if you have been to any commercial gym in the United States, then you have seen an abundance of people vigorously working their abdominals. Typical exercises include crunches and various abdominal machines. While abdominal training is highly important and a good means to improve stability, reduce injury, and maintain mobility, those isolation exercises you see most gym-goers performing just may not be the optimal way to improve the core muscles (abdominal and lumbar muscles).
A recent study in the United States was done to determine whether integration core exercises, which require activation of the distal trunk muscles (deltoid and gluteal), resulted in greater core activation than those of the isolation exercises that utilize only the proximal trunk muscles.1
The study that was performed took twenty participants, ten healthy men and women (all were college students). Each participant was required to meet the ACSM weekly guidelines for physical activity of 150 minutes of moderate-intensity cardio, 2-3 days of weight training, and 2-3 days of flexibility exercises. Both proximal and distal muscles (six total core muscles) had surface muscle activity tested via electromyotherapy (EMG). These tests used a random sequence of sixteen isolation and integration core exercises.2
The overall results revealed that the activation of the abdominal and lumbar muscles was the highest during the integration exercises that required activation of deltoid and gluteal muscles. The integrated exercises also challenged coordination and balance. The study revealed that the abdominal and lumbar muscles were activated the most when balance was challenged.3
The integrated core exercises yielded a greater activation than isolation exercises in various muscles: the rectus abdominus, external abdominal obliques, and the obliques. There was even one integrated core exercise that resulted in 200% greater activation in the obliques than that of the isolation exercises. One other significant discovery in this study was that complex movements stimulate the targeted muscle groups as well as other primary muscle groups.4
These results suggest that integration exercises that require distal trunk muscles to be activated could potentially be optimal for maximizing strength, improving endurance, enhancing stability, reducing injury, and maintaining mobility, with reducing injury being possibly the most important. Recent studies revealed that college athletes who were injured had a weak core, primarily in the hip abductors. Having those athletes participate in a core strengthening program resulted in fewer knee-related injuries.5 Core strength is also vital in protecting the spine and preventing lower back injuries. When the core is weak, additional stress is applied to the spine, and back injury or pain is more likely to occur.6
This article is not suggesting that your core-strengthening regimen should neglect core isolation exercises, but it is simply reiterating that integrated core exercises are more effective at activating core muscles. When optimal performance is the focus, then a program that utilizes more integrated core exercises would be ideal. Next time you are in the gym, think twice about jumping on that abdominal machine – “integrate” a core exercise instead!