In this final part of our series on suspension training we’ll examine the effectiveness and efficacy of suspension training. Efficacy is defined as the ability to produce a desired or intended result, for example “there is little information on the efficacy of this treatment.” Conversely, Effectiveness is defined as being successful in producing a desired or intended result, “effective solutions to environmental problems” for example. However, when it comes to science and research the two words have more specific meanings. Basically, efficacy is a measure of whether or not something works whereas effectiveness is concerned with whether or not it can be used practically. That is to say that there are many things (tools, treatments, etc) that are efficacious but due to their cost in dollars or time or other factors, they may not be practical to use or be effective in practice. More on the difference of efficacy and effectiveness here.
Suspension Training Efficacy
One study published in the Journal of Strength and Conditioning Research called Effect of Using a Suspension Training System on Muscle Activation During the Performance of a Front Plank Exercise found that “abdominal muscle activation was higher in all suspended conditions compared to the floor based plank.” This is in line with the marketing and purported benefits of suspension training. The study found specifically that “The highest level of abdominal muscle activation occurred in the arms suspended and arms/feet suspended conditions, which did not differ from one another.” So, some amount of instability or suspension is beneficial but more is not necessarily better. The study also found activity in the two joint quadriceps muscle that crosses the knee and hip joint and in an important shoulder/scapular stabilizer the serratus anterior, “Rectus femoris activation was greatest during the arms suspended condition, whereas SA activity peaked during normal and feet suspended planks.” The authors concluded that “These results indicate that suspension training as performed in this study seems to be an effective means of increasing muscle activation during the plank exercise. Contrary to expectations, the additional instability created by suspending both the arms and feet did not result in any additional abdominal muscle activation.”
The protocol in the study consisted of performing 2 repetitions each of 4 different plank exercises for 3 seconds each, three of which were using a TRX Suspension System;
- floor based plank
- planks with arms suspended (TRX)
- plank with feet suspended (TRX)
- plank with feet and arms suspended (TRX)
21 subjects participated and the muscle activation was recorded from rectus abdominis, external oblique, rectus femoris, and serratus anterior (SA) muscles using electromyography. In practice, trainers and exercisers tend to hold the plank position for more than 3 seconds which brings up the question of what happens as the person holds the plank suspended or unsuspended for a longer time and how applicable are these results if in practice the plank is held for longer periods.
Another study in the Journal of Strength & Conditioning Research titled Activation of Spinal Stabilizers and Shoulder Complex Muscles During an Inverted Row Using a Portable Pull-up Device and Body Weight Resistance found that Four inverted row exercises studied activated the LD (latissimus dorsi), UT (upper trapezius), MT (middle trapezius), LT (lower trapezius, and BB (biceps brachii) at levels conducive to strengthening. This seems to show that a suspension training apparatus, in this case a “portable pull-up device” is an appropriate substitute to free weights for creating the resistance necessary to build strength. 13 male and 13 female subjects participated in the study. Interestingly, the investigators reported that “No statistically significant differences in muscle activation existed between single- and double-leg WB (weight bearing) in any muscles.”
When examining push up exercises the study Analysis of Pushing Exercises: Muscle Activity and Spine Load While Contrasting Techniques on Stable Surfaces With a Labile Suspension Strap Training System also from the Journal of Strength & Conditioning Research found that ” In general, the instability associated with the labile exercises required greater torso muscle activity than when performed on stable surfaces.” The researchers also found it interesting that ” a standard push-up showed significantly greater shear than TRX angle 1 (p = 0.02), angle 2 (p = 0.01), and angle 3 (p = 0.02).” This study used kinematic analysis of body segments and muscle activity in a 3D model of 14 men to estimate muscle force. They compared exercises performed using stable surfaces for hand/feet contact and with labile suspension straps. A metronome was used to control speed of movement for each exercise.
To quantify the load at different angle of the push up, Effects of Angle Variations in Suspension Push-up Exercise in the Journal of Strength & Conditioning Research examined this question. The study used 28 male subjects and compared forces during push ups at 4 different body angles (0, 15, 30, 45°) while using a TRX suspension training device. The results showed that “as the TRX angle was reduced, the load applied to the TRX straps increased…” This was true during the concentric and eccentric phases of the exercise, e.g. “for both the elbow joint changing from flexion to extension and vice versa.” The greatest forces were recorded at 0°. Forces equal to 50.4% of the subjects body weight were recorded when their elbows were extended and 75.3% of their body weight when the subjects elbows were in the flexed position.
Electromyographical Comparison of Pike Variations Performed With and Without Instability Devices also in the Journal of Strength & Conditioning Research found that there were “significant differences between the instability devices and the stable pike. These results indicate that with more freely moving instability devices (e.g., suspension device, Swiss ball, etc.), core musculature may require greater muscular demands.” The study compared the EMG results of 20 men and women performing 5 variations of a pike on varying surfaces –
- stable ground [PK]
- Swiss ball [SB]
- suspension training device [ST]
- BOSU ball [BOSU]
- Core Coaster [CC]
Two additional studies looked at the influence of suspension training on hormone responses. Both these studies – Effects of Suspension Training on the Growth Hormone Axis and Anabolic Hormonal Responses to an Acute Bout of Suspension Training were publish in the March 2011 issue of Journal of Strength & Conditioning Research. Additionally, both studies, which were similar in protocol were funded by The Citadel Foundation and Fitness Anywhere, Inc. Fitness Anywhere is the parent company of TRX. The both the growth hormone study and the anabolic/testosterone study used a 60 minute suspension training interval workout that consisted of 23 exercises performed for 30 seconds each followed by 60 seconds of rest. The results of both studies showed positive increases in hormone levels similar to those achieved in high intensity circuit type training with free weights or other modalities. The growth hormone study concludes “These data indicate that a suspension training workout using the recommended 30 sec:60 sec work:rest ratio is sufficient to stimulate the GH axis in recreationally active young adult males. Practical Applications: This evidence supports the use of suspension training as a stimulus for anabolic hormone release, suggesting this is a viable alternative to traditional resistance training for stimulating the anabolic hormones that support recovery and muscle growth. ” The anabolic/testosterone study concludes “A suspension training workout using 30 sec work intervals followed by 60 sec rest periods elicited typical TT and novel T:C ratio responses to moderate intensity resistance training in physically active males. Suspension training appears to stimulate an expected testosterone response with a lower associated stress (i.e. cortisol) response resulting in a positive anabolic profile lasting at least two hours after the workout. Workouts using 30 sec work and rest intervals, 45 or 60 sec work and 30 or 45 sec rest intervals may likely result in more robust hormonal responses.” Both studies state that their results support “the use of suspension training exercise as a viable alternative mode of exercise to traditional resistance training. ”
No studies that I have found have investigated the use of suspension training straps for lower body exercises such as hamstring curls, hip bridges, or squats. Additionally, I have not found any investigations into the use of suspension straps for plyometric or jumping type exercises for metabolic or power training. It seems to me that the use of suspension training straps for these types of exercises is superfluous. A function of choreography and class or session logistics rather than a function of efficacious or effective exercise selection.
When compared to needing a gym with hundreds of thousands of dollars worth of equipment, it’s clear that the use of suspension training apparatus can be effective as well as efficacious. When compared to a calisthenic program that uses full pull ups and handstand push ups, the suspension trainer can be a way to regress or lessen the loading for those not able to perform full push ups, pull ups or other body weight exercises. Suspension training straps can also be a way to assist lower body exercises like squats or single leg squats making them accessible to those that cannot yet perform them with their full body weight.
However, when looking for a place to suspend a suspension trainer, the effectiveness of the products is not as great as imagined. Note that there are many anchoring systems and frames sold to allow one to use these suspension devices in gym and class settings because finding anchor points is not as easy as one would think. As a person that lives in an old house (see video) the door mounting devices also fall short in utility because I don’t have room in the hallways to use the devices. As someone that works in NYC, the Parks Department is not amenable to using trees to attach suspension devices either.
As debates continue regarding open chain vs closed chain exercises, stable vs unstable surfaces, and functional vs aesthetic exercises it’s also interesting to note the differences between object manipulation and body management skills. Body management, object manipulation and locomotion skill are the three areas of physical literacy suspension training clearly falls under the body management category but doesn’t satisfy the object manipulation or locomotion skill categories. Suspension training shouldn’t be the only source of resistance exercise in a program.