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Undersun Fitness’ Frequently Asked Questions

  • What is Time Under Tension (TUT)?

    In any given rep or set structure, it isn’t just about how many reps you do, that determines how hard a muscle works. What you’re really looking at is Time Under Tension (TUT) which is the total time that your muscle is under tension in the concentric, isometric and eccentric phases. If you have a 1-second concentric contraction, a half-second isometric and a 2-second eccentric, then your TUT per rep would be 3 ½ seconds. If you take the number of reps and multiply it by the TUT, you get the total Time Under Tension for the set. 

    If we look at the TA2 program, in Sets #2 and #3, we have a rep speed of approximately 3 ½ seconds, multiplied by 10 reps, which gives us a TUT for that set of roughly 35 seconds. The ideal TUT for muscle size and strength gains (hypertrophy) the ideal range is 30-70 seconds. In Set #4, although we have 15 reps as opposed to 10, our TUT is very similar. Let’s compare: Using an explosive rep speed of less than 1-second on the eccentric and concentric, and no pause on the isometric, we have a TUT per rep of less than 2-seconds. Multiply that by our 15-reps and we have roughly 30 seconds.  As you can see, although we’re doing more reps, our TUT is less, but still in that ideal range for building muscle.

    One of the peripheral benefits of Set #4 is that we’re also driving more blood into the muscle. Besides the fact that we all like the way a good muscle pump feels, it also serves a muscle building purpose. By driving more blood into the muscle, along with it comes muscle building nutrients like glucose and amino acids.

  • Why are all the month-1 exercises unanchored?

    By learning all the exercises that you can do, by anchoring the band with only your body, you are creating an arsenal of exercises that you can do virtually anywhere. This way even if you don’t have an anchor point, you’ll never have to compromise one of your workouts. So think of Month-1 as not just an introduction to resistance band training, but also as your foundation exercises.

  • How many sets do I do?

    For each exercise, in the TA2 Muscle Building Program, you will be doing 4 total sets.  

  • How long is the rest between each exercise?

    To shorten your workout time, and keep the intensity high, it’s recommended that you only rest 60-seconds between exercises. This is going to keep your heart-rate elevated as well, which will have a calorie burning effect. If you need more rest time, go ahead and take it. As you progress through the program just incrementally shorten your rest periods and try to get down to that 60-second mark.

  • Is there a heavier resistance level than the extra-heavy band?

    One of the great things about resistance bands is the portability, so why haul around more bands than you need? If you want to go heavier than the X-Heavy band, just stack it with another band for more resistance. For example, the X-Heavy band paired with the Heavy band equals a maximum resistance of almost 200 pounds. That’s a lot of resistance for 2 bands that barely weigh more than a pound.

  • What are the different resistance levels of each band?

    The level of resistance varies depending on how much the band is stretched, but the chart below gives an estimated average range of resistance per band. 

    • X-Light resistance band: 5-15 pounds
    • Light resistance band: 15-25 pounds
    • Medium resistance band: 30-60 pounds
    • Heavy resistance band: 45-100 pounds
    • X-Heavy resistance band: 50-120 pounds 


  • How does the TA2 HIIT & Tabata program work?

    The TA2™ program consists of alternating rounds of HIIT and TABATA, utilizing Undersun Resistance Bands. Each round is made up of multiple exercises, each targeting specific muscle groups. The sequence of each round is designed to maximize the energy and intensity of the workout, yet provide adequate recovery time. These workouts are short in overall time but are fun and highly effective.

  • How many reps do I do?

    The TA2 Muscle Building Program was designed using a 20/10/10/15 Rep Structure, popularized by TA2 Co-Creator, James Grage.