Does Exercise Variation Affect EMG-Measured Muscle Activation in Upper and Lower Limbs

Assessment 2: Applied Project Written Assignment (30%)

Due Date: Friday 7th June 2024 5.00pm (week 14)

Length: 2500 words (total for both upper and lower body essays) this is simply a recommendation and not a requirement to reach this number of words. You will only be penalised for going over this limit, not for falling short of this word count should you still cover all required content to a high standard - prefer page limit with appropriate formatting see below and example later on vUWS

Submission Details: Electronic submission via Turnitin. Format for assignments must be double spaced, 12-point font, using a Vancouver referencing style. The total length should be approximately 9-10 pages maximum.

Note: See other Assessment resources in the Assessment Zone on vUWS for further details.

Feedback Details: written feedback will be provided.

Rationale

The premise of this assignment is based around examining whether different exercise variations for the upper and lower limb affect muscle activity.

Task

Work in small groups to facilitate data collection. Each student needs to have a signed off data collection sheet (checked off by the tutor), having completed the required upper and lower body exercises.

There will be an introduction and demonstration to surface electromyography (EMG), AND SAFE USE OF THE SAFETY RAZORS AND OTHER EQUIPMENT.

The assignment will require you to collect data from two upper body muscles during four different shoulder girdle movements, and from two lower body muscles during four leg exercises.

For the upper body you will measure the muscle activity from pectoralis major (PM) and triceps brachii, lateral head (TB).

For the lower body you will measure the activity from the vastus lateralis (VL) and gluteus maximus (GM).

Site placements

The following sites describe the placement of the centre of the first electrode applied.

Pectoralis Major (PM): Position first electrode 11cm below inferior border of clavicle and 7cm medial to anterior axillary line. Aligned at 45 degrees, with second electrode placed inferiomedially to the first.

Triceps Brachii (TB): Positioned at 50?romion to olecranon distance. Place second

electrode directly above the first, aligned vertically.

Vastus Lateralis (VT): measure the distance from the anterior superior iliac spine to the superior aspect (base) of the patella. Place the first electrode on VL at 50% of this distance, with the second electrode aligned at a slight angle on your best estimate for where contracting muscle can be represented.

Gluteus Maximus (GM): Find 50% distance between left and right posterior superior iliac spines to locate sacral start point. Position first electrode 40% distance between sacrum (as found) and greater trochanter. Place second electrode inferiolaterally to the first. You can prep and apply the electrodes in the changing rooms if you are more comfortable, so only the wires are coming out of the top of the waistband when returning to the lab.

Experimental Procedure

1. Familiarization with all exercises
2. Site preparation and electrode placement
3. Confirm signal from muscles of interest
4. Perform warm-up contractions for each muscle
5. Perform 3 maximal voluntary contractions (MVC) for each muscle (when you are measuring from it, i.e. if you do a leg extension but have electrodes on PM and TB, you arent really measuring from the right muscles)
6. MVC techniques should all be maximal isometric contractions.

PM: Starting prone in bottom push up position with arms at 45 degrees from your sides, hand placed 1 bioacromial width apart at height of the sternal head of pec. Have tester resist push up movement at a horizontal humeral angle. Resistance must be sufficient enough that no movement is allowed.

TB: Measured during the same MVC procedure as PM.

VL: Subject assumes a bottom squat position inside power cage with barbell on back. Spotting supports need to be position at a height that stops the subjects movement as their thigh reaches a position parallel with the ground. Once spotting supports are in place, subject drives out of the bottom position until the barbell meets the spotting arms which will resist the max effort contraction.

Week 6 Pilot testing only: Use a maximal isometric knee extension (have individual lie on floor, hip to 45 degrees and knee flexed to 90 degrees, foot flat on floor have partner resist extension as much as possible).

GM: Measured during the same MVC procedure as VL.

Week 6 Pilot testing only: Lying supine, position the thigh at maximal hip flexion while maintaining neutral pelvic angle. Have tester resist maximal active hip extension movement. Resistance must be sufficient to restrict any thigh movement. A second tester will be required to resist the shoulders from sliding backwards.

Upper Body Exercises

1. Low Incline Dumbbell (DB) Bench Press, 2 level elevation of the bench (load should be 4/10 on RPE scale, hands to pass chest at bottom and elbow to reach full extension at top)
2. Flat Barbell Bench Press (load 4/10 on RPE scale, weight to touch chest at bottom and elbows to reach full extension at top)
3. High Incline Dumb-Bell Bench Press, 4 level elevation of the bench (add load for 4/10 intensity on RPE scale)Flat DB Bench Press (4/10 RPE for applied load)
4. Flat DB Bench Press (4/10 RPE for applied load)

Lower Body Exercises use controlled cadence for all exercises, i.e. no bouncing. Repetition tempo for all exercises is 3030. For leg press movements ensure the femur/thigh reaches a vertical, 90 degree position relative to the bench; for all squats ensure depth reaches parallel (i.e. thigh is parallel to the floor). For leg press and squats ensure foot width is just outside the hips, with the thigh partially externally rotated. Repetition tempo for all exercises is 3030.

1. Isolateral Leg Press (3/10 RPE loading applied)
2. Front Squat (3/10 RPE loading applied)
3. Back Squat (3/10 RPE loading)
4. DB Split Squat (3/10 RPE loading)

In the final assignment students will need to submit a completed Experimental Checklist (signed off by their tutor when completed), or 10 (out of 30) marks will be deducted from their final assignment grade. This will ensure all students have taken part and engaged in the laboratory procedures. The page of this document that has been signed off must be scanned and submitted with the assignment as a secondary submission in PDF format.

You have to have a go!!!! Its not about getting it right, but TRYING

You will be required to analyse your EMG data. The maximal activity for every repetition will be recorded, and must be normalized to the MVC for each person. This means that the muscle activity will be expressed as a percentage of maximal activity.

For example, if muscle activity was 1mV during an exercise, and the MVC recorded for that muscle was 2mV, then the normalized muscle activity is,

1mV (during exercise) / 2mV (highest during MVC) * 100 = 50.0%

EMG VALUES FOR MVCS (fill these in here only)

The values for the MVCs will be used on the subsequent pages for the respective muscle.

DO NOT divide the muscle activity for PM by the maximal voluntary contraction for VL.

Has the tutor seen me doing any of the exercises, or came over after I finished and had multiple group members confirm that I did the exercises?

Has the tutor seen me having a good honest go at processing EMG data for entry onto the following pages? Maybe Im no good at this and didnt end up finishing it all, but did the tutor at least see me giving it a go? (even if I didnt get it right)

UPPER BODY EXERCISES

PM Muscle Activity

TB Muscle Activity

LOWER BODY EXERCISES

VL Muscle Activity

GM Muscle Activity