Training with Intention: Time Under Tension and the Mind-Muscle Connection

One of the most valuable insights I’ve picked up on is the concept of “training with intention.”  I first started weightlifting a few years ago with Strong Lifts 5×5, with the goal of increasing my strength.  I didn’t pay attention to what muscles were contracting – I just wanted to move the weight for the prescribed amount of sets and reps as quickly as possible.  When I started my first bikini prep, I approached bodybuilding as if I was getting ready for a powerlifting meet – I progressively added on weight to my compound lifts and lifted as heavy as I could possibly stand.

Despite my low squat/deadlift/bench/everything numbers, I had fallen into the trap of ego lifting.  Since I trained mostly alone and didn’t send in form videos to coaches, no one corrected me; I spun my wheels for a few months, not growing any bigger despite diligent training.  So when I started training on occasion with a coach in person, I was quickly humbled.  The squat form I was using, while good for pushing weight, was incredibly quad-dominant and didn’t target my glutes.  I hyperextended my lower back during the entire squat, which caused undue stress and back pain.  My lower back would activate during hamstring curls, kicking my hips up with every rep.  All of my shoulder movements were done with poor scapular retraction; so my traps grew larger and my delts stayed small.

Train with intention.  Feel the muscle lengthen, and then contract through it.”

After a few in-person sessions, I changed my form to best target the muscles that I wanted to grow.  I deloaded significantly so that I could 1) spend more time under tension and 2) feel myself contracting through the muscle.  I stopped focusing so much on the weight I was moving, and started focusing on chasing that pump.  I breathed through my reps, counting 2 seconds up and 3 seconds down.  I lift the same weights now as I did in 2016, but I look so different:

Left – Sept 2016, ego-lifting; Right – Feb 2018, after an off-season of training with intention

To some extent, ‘training with intention’ refers to both the mind-muscle connection and training with maximal time under tension, which are both backed by research.  The mind-muscle connection refers to intentionally increased muscle fiber recruitment at the microscopic level, namely, at the neuromuscular junction (where the motor neurons interface with the muscle fibers themselves).

This is really exciting.

Contreras (2014) in a pilot study found that experienced lifters could change EMG activation without changing form or stances, alternating squats between quad and glute focused, deadlifts between hamstring and glute focused, and rows between lat and bicep focused, among others.  Through conscious thought and muscle loading, lifters could preferentially activate certain muscle groups over others.

He concludes, “Form needs to be solid, but simply observing movement from the outside doesn’t completely tell you what’s going on under the hood. The underlying muscles also need to be firing in proper amounts and in proper combinations during movement for optimal performance, and these amounts and combinations likely differ depending on whether the goal is to develop maximum strength, endurance, or activation.”

The goal for bodybuilders is developing maximum activation and generating metabolic stress.  This leads to increased muscle protein synthesis.

Burd et al. (2012) recruited 8 men who had weight-trained into their study to test whether exercise tempo (time under tension) affected muscle protein synthesis.  Each participant was his own control – one leg would do knee extensions at a tempo of 6 sec up/6 sec down to failure, while the other leg would do the same exercise at a tempo of 1 sec up/1 sec down at an equivalent load and match the number of reps.  This was repeated for 3 sets at 30% of the participant’s 1 rep maximum.  Participants then drank 20g of whey protein (with a tracer material) immediately after exercise and 24 hours after.  Biopsies from both legs were taken at 6, 24, and 30 hours post exercise.

Furthermore, they actually measured time-under-tension:  “Muscle time under muscle tension was greater for each exercise set (all, P < 0.05) in the SLOW [6 up/6 down] condition (set 1, 198 ± 10 s; set 2, 119 ± 9 s; set 3, 90 ± 7 s) compared to the CTL [1 up/1 down] condition (set 1, 25 ± 2 s; set 2, 14 ± 1 s; set 3, 11 ± 1 s) with a similar ∼8:1 ratio between contraction times for each set in the SLOW condition as compared to CTL. The total time the muscle was under tension was greater (P < 0.001) in the SLOW (407 ± 23 s) as compared to the CTL (50 ± 3 s) condition.”  For the leg that performed slower reps, the myofibrillar protein synthesis rate was higher and exercise-induced rates of mitochondrial and sarcoplasmic protein synthesis were elevated.  In other words, slower reps = more gains.

Lacerda et al. (2016) went further in testing the time-under-tension theory, and put 22 exercise-trained males through either Protocol A or Protocol B for bench press.  The time under tension, number of sets, and % of 1-rep max for either Protocol A or B were the same.  However, Protocol A consisted of 6 reps (6 seconds per rep) and Protocol B consisted of 12 reps (3 seconds per rep), for a total of 36 seconds under tension per set.  These researchers found that EMG activation and blood lactate levels were increased in Protocol B, suggesting that higher reps may be more effective in creating metabolic stresses conducive to muscle hypertrophy.

When you perform reps slowly, you cannot rely on generated momentum to move the weight – your muscles have to contract the whole time, rather than explosively at the bottom of the lift.  By taking out the momentum from the lift, you also take the tension off of your more delicate soft tissues, such as your joints and tendons, decreasing your chances of injury.  Furthermore, when you perform reps slowly, you can focus on maximally activating the targeted muscle.  I personally had another heaping serving of humble pie when I carelessly strained my rotator cuff.  I had to rehab my shoulder with the physical therapist, using nothing but the weight of my arms for some exercises.  I don’t scoff at the 1 or 3 lb dumbbells anymore.

There are all sorts of tricks for getting a mind-muscle connection going, such as having a training partner tap/touch the targeted muscle, finding cues that work for you, and flexing target muscles with no load.  My favorite cue for dumbbell press, for example, is focusing on moving your biceps towards each other, rather than trying to touch the dumbbells together in front of your chest.

I’d love to hear about your experiences: What cues, tips, and tricks do you have for increasing the mind-muscle connection or training with intention?  Let me know in the comments below!

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