Abdominal Hallowing and Hamstring Injuries

Abdominal Hallowing and Hamstring Injuries

I just got the latest issue of BCAK Kinnected magazine. There were a lot of great articles in it, and they also were kind enough to publish one of mine on abdominal hallowing and hamstring injuries.

I don’t know why I keep typing hallowing. It should be hollowing.

Since it has been printed in the magazine.

It is one of those research summaries I have done several times, and fitness professionals have liked them.

Lower Abdominal Hollowing During Prone Hip Extension May Prevent Hamstring Injuries

What is the Big Deal?

Hamstring injuries are all too common in athletes, especially runners. There is evidence that when the stabilizing muscles in the hips (e.g., the gluteus maximus) become tired, the increased workload is placed on other muscles in the legs, including the hamstrings. This disproportionate amount of work required by the hamstrings often results in injury.

Details of the Study

Research published in Manual Therapy recently examined whether adding lower abdominal hollowing exercises to Prone Hip Extension (PHEactivitieses. It would improve the relative timing of the gluteus maximus (GM) and Biceps Femoris (BF) in the hamstring muscle group.

A total of 20 subjects (five males and five females) were randomly divided into two groups. One that performed PHE exercises with abdominal hollowing. And one that conducted PHE exercises without abdominal hollowing. The volunteers were assigned to perform PHE exercises plus abdominal hollowing. They completed ten abdominal hollowing contractions lasting 10 seconds each, with 10-second resting periods in between the contractions. In contrast, the second group did the same without performing abdominal hollowing. They were then given a two-minute relaxation interval, followed by a repeat of the ten contraction-rest cycles. The volunteers assigned to perform PHE exercises only completed regular PHE exercises using the same schedule as those in the PHE + abdominal hollowing group.

Hamstring Injuries

What did They find?

The investigators found that the two volunteer groups had very different levels of GM firing relative to BF before completing the exercise programs. When looking at the differences in GM firing close to BF after the participants completed the exercise programs, the relative timing had improved in the group performing abdominal hollowing compared to the group only performing PHE exercises. Still, this difference did not reach statistical significance (p.166).

The authors concluded that their results show that short abdominal hollowing repetitions during PHE exercises may reduce the delay between the muscle firing in the GM and BF. Still, we need to do more research to confirm these findings. Their study’s lack of statistical significance may be due to the small sample size or a small effect size of the abdominal hollowing exercise regimen.

If this all sounds too familiar, it is what I go through in Muscle Imbalance Revealed.

Source: MANUAL THERAPY (2009 Aug 11. [Epub ahead of print]).

Where Can I Get More Information on Abdominal Hollowing?

Hamstring Injuries

You can attend my live course on Core Stability for the Rehab client. I go through my technique regarding abdominal hollowing and how it is a vital step in rehabilitation and the core stability continuum. I don’t teach the course often, maybe one time a year. The next time was in October 2011. I also had a DVD of the presentation. To get more details on the DVD, click here.

I don’t think I can give you the link to the magazine, but if you want a full copy of it, contact the BCAK.

Rick Kaselj, MS

Hamstring Injuries