Scap Activation: 90/90 to Y Slides vs the Classic Prone Y Exercise

By |2022-11-30T13:20:12-05:00December 4th, 2022|Latest Articles|

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We used the mTrigger biofeedback [system] to measure the amount of Lower Trap and Middle Trap Activation when performing two common scapular exercises:

– Tripod Y Raise (Former Gold Standard for Low Trap*)
– Tripod 90/90 to Y Slides

Surface EMG measures the amount of electrical activity in the muscle directly under the pad, which is how we are able to measure the activation of these muscle groups.


  • In this particular example, surface EMG is measuring the muscle activation of the lower trapezius / middle trapezius muscle during the prone Y and Y slide exercise. By measuring the electrical activity of the muscle, the clinician is able to gather key pieces of information on the patient’s performance of the selected exercise. In this instance, sEMG biofeedback picks up the level of muscle activation of the middle/ lower trap and provides specific information on the level of muscle activation (peak and average) and timing of muscle activation during the entirety of the exercise.


We found that the MAX recruitment was slightly higher with the Y slides than it was with the prone Y, although they had pretty comparable peak activation numbers.


  • There are a few different ways to track muscle activation data during an exercise. In TRAIN mode, you can record an exercise. This allows you to save data and review it afterwards under the TRACK tab. When viewing an exercise in TRACK, you will see a graphical representation of muscle activation levels compared to the goal activation level. This conveys a few different pieces of information:
    1. Peak Muscle Activation: represented by the tallest “peak” on the graph and the corresponding number on the y axis
    2. Average MVC: the average activation of the target muscle during the contract phases of the exercise. Viewed by tapping the graph.
    3. Work under the curve: the total amount of work a muscle is doing throughout the exercise. This is a combination of the level of muscle activation and the sustained time of activation. This number is not expressly reported by the mTrigger app, but here it is interpreted via the level of the meter in the Train screen.

The HUGE difference was that the Slides maintained these high levels of recruitment throughout the entire Range of Motion and whereas the “Y’s” only approached their peak at the top of the lift

  • mTrigger biofeedback can provide insight on how range of motion and position effect muscle activation levels. This offers invaluable information to both the patient and the clinician. Visual biofeedback allows patients to better understand how and when to activate a muscle during a movement (e.g., the prone Y exercise). When patients are able to see a muscle activating, they can better self-correct and adjust to properly execute the desired exercise. For the clinician, surface EMG biofeedback provides an understanding of when a muscle is most active during an exercise. In the case of the Y slide, we can see that the range of motion during the exercise is less, therefore the lower / middle trap muscle maintains a more constant level of sustained activation throughout a larger chuck of the exercise. The prone Y exercise on the other hand has a larger range of motion and in this case, demonstrated a higher peak activation at the top of the motion. For this example, activation was measured as a continuous exercise motion (no rest). Variables such as peak, average MVC, and “work” under the curve can change when reps, on time, and rest are programed differently.



We believe the 90/90 to Y slides do a better job of maintaining recruitment due to the position force feeding all 3 Primary Scapular Motions of the Low Trap:

-Horizontal Abduction Scap Retraction
-External Rotation Scap Posterior Tilt
-Slide To Y Scap Upward Rotation

That is the Lower Trap Trifecta

Clinically, we have had a lot of success in using many different exercises to zero in on the low trap but very few have studied how they compare to the Gold Standard “Y Exercise”

This is just Step 1 in Exploring some alternative Low Trap Exercises and does NOT mean to stop doing your Y’s

  • When performing scapular exercise, adding mTrigger biofeedback is an excellent way to execute exercises with accuracy and track results. You miss that which you don’t measure.

There are a TON of limitations to this Case Study and this is just step 1, but we wanted to explore our curiosity and see if there was any substance to what we were seeing clinically.

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