Suspension Exercise: The Research
by Tony Nunez, MS and Len Kravitz, PhD
Suspension exercise combines body weight and anchored, seatbelt-like straps to provide an alternative to free weights and machines. The question on a lot of trainers’ minds is whether these strap-based training systems work as well as more traditional resistance training tools. Though research into this question has been somewhat sparse, studies are starting to paint a picture of effective ways to integrate suspension exercise into a workout program.
(Note: Suspension Training™ and Suspension Trainer® are trademarked terms owned by TRX®. This article uses the generic terms suspension exercise and suspension exercise device.)
A Brief Overview of Suspension Exercise
Suspension straps are usually anchored to a fixed point about 6 feet above the floor or higher. Research studies often call them “labile” straps, denoting their unstable nature.
Though suspension exercise looks a bit like the still-rings event in men’s gymnastics, the similarities are few: In the rings event, the hands remain in contact with the still rings, the legs are off the ground, and the body continually performs gymnastics skills below, above and around the rings. In suspension exercise, the arms and legs are placed interchangeably in the device, and exercises progressively and specifically challenge the musculoskeletal system.
Perhaps the best-known suspension exercise device is made by TRX®, founded by former U.S. Navy Seal Randy Hetrick, who developed the product while on active duty because he needed to stay in shape but had no access to free weights or machines. Today, a few companies are making suspension devices. The aim is to increase the body’s functional movement capabilities by improving core muscle activation, posture, coordination, upper- and lower-body strength, total-body joint flexibility and dynamic balance.
Emerging research from the peer-reviewed studies summarized below illustrates some of the physiological benefits of suspension exercise. We have divided the studies into two broad research categories:
- suspension exercise and core activation
- suspension exercise vs. traditional resistance training
Suspension Exercise and Core Activation
Suspension exercise devices are inherently unstable, requiring users to engage many muscles—particularly the core musculature surrounding, stabilizing and protecting the spine—to maintain optimal bodily form during exercise. Several research studies have addressed questions related to core activation during suspension exercise.
Low-Back Loading and Stiffness During Suspension Push-Ups
Beach, Howarth & Callaghan (2008) conducted a study that asked: Do the advantages outweigh the risks when performing suspended push-ups to activate the abdominal muscles?
Push-ups are workout mainstays because they can increase upper-body strength and endurance, while also requiring a great deal of core muscle activation to maintain proper form and position. Beach and colleagues investigated whether push-ups performed with a suspension exercise device require greater abdominal-wall and latissimus dorsi activation than traditional push-ups.
Eleven recreationally trained men (average age, 27) volunteered for the study. They all performed both the traditional push-up and the suspended push-up, completing one set of each—eight to 10 repetitions—with 2 minutes between sets to avoid fatigue. In the suspended push-up, participants’ feet were stabilized on a solid platform and the hands were placed in the suspension device. Exercise order was randomized.
Familiarization trials before data collection ensured proper form, technique and rate of repetitions. Infrared light-emitting diodes were placed on the subjects to let researchers view kinematics, and electromyography markers on seven bilateral trunk muscle groups—rectus abdominis, external obliques, internal obliques, latissimus dorsi and erector spinae at T9, L3 and L5—provided EMG data.
Results showed that suspended push-ups generated more muscle recruitment of the abdominal wall and latissimus dorsi than standard push-ups. Average activation levels of the rectus abdominis, external abdominal obliques, internal abdominal obliques and latissimus dorsi were, respectively, 184%, 46%, 54% and 59% greater during suspended push-ups than they were during standard push-ups.
Suspended push-ups also produced greater compressive forces at L4/L5 of the lumbar spine than traditional push-ups, but the authors noted that the forces did not exceed established values for safe spine loading. The authors cautioned that while greater compressive forces can enhance spinal stability, the bigger loads increase the risk of pain in people with lower-back issues.
Take-home message: Suspended push-ups produce significantly greater challenge to the trunk muscles, latissimus dorsi and spine than standard push-ups. People with lower-back issues should proceed cautiously if performing suspended push-ups.