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8 weeks with Cosgrove and JB – The results


Everyone wants to know: What is the best program for weight loss and performance? We tried to answer this question by comparing three programs in our Informal Experiment… and the results were surprising.

Back in January we asked for people interested in taking part in a particularly cool informal experiment. And boy were they interested! Within 24 hours we had more people than we knew what to do with and had to limit the number of participants to fewer than 150. We guess getting 8 weeks of training designed by Alwyn Cosgrove, JB, and Fraser Quelch was a big draw.

The experiment compared the effectiveness of three similar, but distinct, different strength and conditioning programs for fat loss and overall fitness.

1.  One was a strength program that also included steady state cardio: get on the treadmill at a given speed and go for 30-45 minutes.

2. One was a strength program that also included interval training (aka high intensity interval training or HIIT): get on the treadmill and run really fast, take a short break, and repeat for a given number of rounds.

3. And the final group was a strength program that also used suspension training (aka TRX training) as part of their conditioning work. Don’t know what suspension training is? Well, read on.

In this study, we asked three questions. Which of these three programs:

  1. Would most effectively improve performance?
  2. Would most effectively promote weight loss?
  3. Would people find most fun, and thus, stick with the longest?


The testing

We compared the programs based on two indicators: body weight and performance.

Assessing body weight was easy: Participants simply recorded their weight once a week during the study. By the end of the study we had 9 body weight measurements to compare from week 0 to the end of week 8.

Measuring performance was a little more intensive. Before the study began, and after it ended, everyone did the following five performance tests:

1. Maximal push-up test: You’ve probably done this at some point in your life and it’s pretty straightforward. After a 5 minute warm-up, use a 2″ sponge or yoga block as a depth marker and do as many consecutive push ups as you can. Start with the arms in full extension, descend to the depth marker, and extend back up. This counts as one repetition. Do as many as you can without resting. Once you’re finished, record your number.

2. Inverted row test: With your feet elevated on a Swiss ball, box, or bench and your arms gripping a barbell or Smith machine bar, do as many inverted rows as you can. Start with your arms fully extended, pull up until your chest touches the bar, and extend back down. This counts as one repetition. Do as many as you can without resting. Once you’re finished, record your number.

3. Standing broad jump test: Choose an open area and using a countermovement knee bend, jump as far forward as you can, going for maximum distance. Start with two practice jumps, aiming for about 80% of your maximum distance. Then, on your third jump, give it your all. Have someone mark where you landed and measure the distance from where your toes started to where they landed.

4. Treadmill V-max test: Perform this one on a treadmill. Begin by running at 7-9 mph (choose 7 if you’re not a very good runner and 9 if you’re a good runner) and 0% elevation. Every minute, increase the elevation by 1%. Continue this until you simply can’t continue running. Go to complete exhaustion. (Flying off the back of the treadmill counts as complete exhaustion.) Once you’re finished, record the speed and elevation at which you stopped. These numbers represent your V-max.

5. Treadmill T-max test: On another day, after a 5 minute warm-up run, set the treadmill to your V-max (speed and elevation recorded above). Run as long as you can. Go to complete exhaustion again. Once you’re finished, record the total time you lasted. This represents your T-max.

Thus at the end of the study we had before/after body weight measures as well as before/after performance changes to compare between groups for the entire 8 week study.

The three groups and their workout programs

We split our participants up into 3 groups:

1. A steady state cardio group

2. A sprint interval group

3. A TRX conditioning group

All three groups did the same strength training program, designed by Alwyn Cosgrove, which consisted of 2 days of strength training per week.  Every 4 weeks, the strength workouts changed.

After that, our groups diverged. So, everybody (all groups) did exactly the same strength workouts, but the conditioning workouts were different.

1. Steady state cardio = 2 weight training workouts, 2 steady state cardio sessions per week

2. Sprint interval = 2 weight training workouts, 2 interval sessions per week

3. TRX conditioning = 2 weight training workouts, 2 TRX conditioning sessions per week

The conditioning workouts changed every 2 weeks.

Conditioning workouts were either about a half an hour of “steady state” aerobic conditioning, interval training or suspension circuit training. And all 3 groups got progressively harder workouts each week.

OK, we can hear the outrage now. You’re probably thinking that an half an hour of steady state doesn’t burn the same calories as interval or suspension training. So how can we compare?

Yes, it’s true that steady state doesn’t burn as much calories. But in real life, people usually go by how much time they have, not how many calories they want to burn. When was the last time you went to the gym and thought: “I only have time for 200 calories”? So we equated the conditioning workouts based on time, not on total calories burned.

Who was in the study?

On average, participants in all three groups were in their early to mid-thirties, although we had participants up to 70 years old (see table below).

Male Female Combined
Steady state cardio (N=17) 35 +/- 6 34 +/- 11 35 +/- 9
Interval cardio (N=23) 36.8 +/- 8. 31.0 +/- 6.8 35.0 +/- 8.1
TRX group (N=16) 33.2 +/- 7.3 36.4 +/- 8.1 34.6 +/- 7.6

Once the participants were selected to participate in the study, they were matched and assigned to groups based on gender, age, weight and training experience. This meant that the groups were very similar to begin with, so any measured effects should be the result of the training intervention rather than individual differences.

Our participants had an average of 9 years’ exercise experience. These people knew their way around the gym.

A few more things…

We wanted to make sure that the results reflected the exercise program, not other factors. So we asked our participants to make a few sacrifices in the name of science.

First, although we didn’t have any dietary restrictions for the participants, we did ask anyone who was currently on a “bulking” diet (weight gaining diet) to exclude themselves from the study or modify their diet.

Second, the participants couldn’t do any other physical activities except activities required for everyday life (such as shovelling snow in February… or in April, for those of you living in Alberta).

Finally, anybody who had specific, short-term performance or body composition goals (such as a 5 k race or a figure competition) were discouraged from participating, as this program was a general, not a targeted, plan. And we wanted to measure what our intervention alone could do.

Study results

What happened: Weight loss

Interestingly, those in all three groups lost weight. Indeed, after 8 weeks, the average weight loss was about 3.2 lbs with no statistical differences between genders or groups. In other words, although all groups lost weight, any apparent differences in table 2 below are likely due to random chance rather than real differences.

Table 2 – Average weight loss (in pounds) over 8 weeks

Male Female Combined
Steady state cardio -3.4 +/- 4.4 -4.9 +/- 4 -4 +/- 4.1
Interval cardio -2.9 +/- 3.8 -0.6 +/- 2.2 -1.8 +/- 3.7
TRX group +4.2 +/- 5.1 -1.1 +/- 3.2 -2.8 +/- 4.5

What happened: performance

Along with weight loss, every group improved their performance — often impressively. (High fives to Alwyn.) But there were no statistical differences between genders or groups; remember, they all did the same strength workouts.

Table 3 – Average change in push-ups after 8 weeks

Male Female Combined
Steady state cardio +9.8 +/- 7.2 +11.7 +/- 5.5 +10.7 +/- 6.3
Interval cardio +10.1 +/- 6.9 +2.7 +/- 6.7 +7.9 +/- 7.5
TRX group +12.4 +/- 9.4 +6.2 +/- 3.5 +9.8 +/- 7.9

Table 4 – Average change in inverted rows after 8 weeks

Male Female Combined
Steady state cardio +4.8 +/- 2.0 +6.9 +/-6.5 +5.7 +/- 4.6
Interval cardio +5.1 +/- 3.8 +2.9 +/-1.2 +4.4 +/-3.3
TRX group +6.8 +/- 4.5 +2.9 +/- 1.6 +5.1 +/-4.0

Table 5 – Average change in broad jump distance (in cm) after 8 weeks

Male Female Combined
Steady state cardio +6.2 +/- 6.5 +5.0 +/- 3.7 +5.7 +/- 5.3
Interval cardio +4.1 +/- 9.4 +6.4 +/- 6.9 +4.7 +/- 8.7
TRX group +4.8 +/- 3.0 2.6 +/-4.4 +3.8 +/- 3.8

Table 6 – Average change in V-max (% grade at constant speed) after 8 weeks

Male Female Combined
Steady state cardio +1.2 +/- 1.2 +1.7 +/- 1.1 +1.4 +/- 1.2
Interval cardio +1.4 +/- 0.9 +1.9 +/- 1.1 +1.5 +/- 1.0
TRX group +1.4 +/- 0.6 +0.3 +/- 0.5 +0.9 +/- 0.8

Table 7 – Average change in T-max (in seconds) after 8 weeks

Male Female Combined
Steady state cardio +128.0 +/- 156.4 +193.4 +/- 145.3 +160.7 +/- 149.0
Interval cardio +80.7 +/- 123.6 +0 +/- 43 +53.9 +/- 112.3
TRX group +78.7 +/- 118.9 +37.4 +/- 63.9 +60.75 +/- 98.1

Fun Factor

While there wasn’t much of a difference between groups as far as weight loss and performance, we noticed a huge difference in the study drop-out rate.  Steady state cardio had a very high drop-out rate, while the TRX group participants were most likely to finish the study.

Table 8 – Drop out rate

Drop out rate
Steady state cardio 80%
Interval cardio 55%
TRX group 35%

Most research labs never have this sort of dropout rate. Because subjects are paid to participate and because they have to report to real-life people, they finish what they start. However, because our Informal Experiments are unpaid and distance-based, it’s easy for participants to blow us off.

Sure, a few will let us know if something happened to exclude them from finishing. However, many of them simply ignore our emails. Even if we were kind enough to send them a workout plan — or even a TRX suspension trainer. Shame, shame. But, no matter. This is what explains the higher drop-out rates seen in a study like this.

However, we’re not sure what explains the higher drop-out rate in the steady state cardio group. For starters, 5 people in the steady state group dropped out the day they received their programs. We figured this was because they assumed steady state cardio sucks (which it does not, when combined with a good strength program). Again, shame, shame.

Of course, injuries are another possibility. But we didn’t get more e-mails from the steady state groups saying they were injured. For the most part any injuries were evenly distributed and mostly non-exercise related (for example, we got a picture of a bruised toe to prove a ladder accident story.) So we doubt that was the problem.

The final explanation could be — simply — that steady state cardio is kinda boring. Not everyone loves the idea of walking on a treadmill for 45 minutes. (Personal trainers everywhere, are you listening?)




All groups saw equal improvements in performance and weight lost. At least, statistically speaking. If you ask me, these improvements were excellent. For example, after just 2 months following the prescribed programs, participants improved their performance by an average of 30%.

This is especially awesome considering that, on average, these people had over 9 years’ exercise experience. Why does this matter? The vast majority of exercise studies use participants with no training experience (aka untrained). And anybody who has trained can tell you that in the beginning you get the biggest improvement.

And yet, in this study, people who had already been exercising for over 9 years saw up to 30% improvement in some performance measures (push-ups, inverted row and T-max) 8 weeks!

Why no difference between groups?

Now, you probably noticed that for push-ups, rows, broad jumps, and V-max, the group means were pretty similar. That’s not unexpected.

While there is literature out there showing the effectiveness of interval training and other types of conditioning exercise vs. steady state cardio for weight and fat changes, there isn’t really any data showing that with a properly designed cross-training program, we should expect differences in key performance variables.(1)

The steady state group did seem to have better T-max scores. Now, again, statistically, there was no difference between groups. However, if there were a slight trend toward a higher T-max, a surrogate marker of anaerobic threshold and aerobic fitness, we would expect the groups that spent the most time on the treadmill to do the best.

So, what’s the take home? Well, around here, most of us do interval training and circuit training (similar to the TRX work) for our conditioning exercise because we find theses types of exercises more challenging, and far more interesting than steady state cardio work.

Maybe this type of training just brings out the masochists in us; we usually alternate between states of:

  • trying to survive the work interval without flying off the treadmill or getting tangled in our TRX
  • dreading the end of the rest interval, thinking, “Is there something wrong with my watch?”

But I think that’s what most folks want in a workout: challenge. And fun.

So, while the performance numbers weren’t really different between groups, something more important was: actually doing the workouts. Remember, 80% of the people in the steady state group dropped out. 55% dropped out in the interval group. And only 35% dropped out in TRX group.

As Woody Allen said, “80% of success is just showing up.”

Weight loss

Participants lost, on average, 3-5 lbs without changing their diets. And if you think this isn’t much, think again. Resent research has shown that exercise alone isn’t very effective without some sort of nutritional change. In fact, many studies have shown no change if a nutrition plan isn’t implemented. Check out this article for more.

The simple fact that weight loss occurred in all three groups of experienced exercisers is very cool.

Why no difference between groups?

Although many people have pooh-poohed steady state cardio for the last few years, when combined with a solid strength training program, steady state cardio can help folks lose weight and improve performance.

That’s right: steady state cardio + strength training has been used – with much success – by physique champions for decades. It works. As does interval work + strength training. As does TRX work + strength training.

Thus, we weren’t surprised at all that there were no differences between groups in terms of weight loss or performance. After all, they did about the same total duration of exercise – 4 sessions per week; 2×45 min strength sessions and 2×30-45min conditioning sessions. So, when total workout times were equated, why should we expect to see anything different?

Now, we don’t have body composition data, as described above. Had we collected those data, perhaps we’d have seen more subtle changes in fat mass and lean mass.

But, truthfully, I doubt it. All three programs included a strength training program and a similar volume of exercise. We have no reason to believe more muscle would have been built and fat lost with any specific intervention.

Bottom line

Here’s how to interpret these results:

When you equate total exercise time, as long as you’re doing an intense, progressive strength + conditioning exercise program, you can feel free to choose whichever program you like best.

If you prefer steady state work, add it in. If you prefer interval work, add it in. And if you prefer TRX style workouts, add them in.  Indeed, in this study, participants seemed to prefer the TRX style workouts. They loved the diversity and intensity associated with this program. So we published the entire 4 phase workout, complete with video demonstrations below.

Phase 1 – Weeks 1 and 2

Phase 2 – Weeks 3 and 4

Phase 3 – Weeks 5 and 6

Phase 4 – Weeks 7 and 8

Of course, to do these workouts, you’d obviously need a TRX suspension trainer.  Here’s how you can get one:

TRX Suspension Trainer

And once you have your TRX system, know that as long as you have a great strength training program, feel free to add in steady state cardio, TRX circuits, and sprint intervals to your heart’s content.


Click here to view the information sources referenced in this article.

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