Muscle Endurance - (Brent Shano)

Research Question and Hypothesis

How does endurance of muscle groups change with time?

Standards

HS-LS1-2 Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multi-cellular organisms.

HS-LS1-3 Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.

HS-ESS3-4 Feedback (negative or positive) can stabilize or destabilize a system.

Experimental Design

The experiment will offer 3 trails to selected participants. These participants will hold two books (one in each hand palm up) with the same specified weight. Here the weight is not a variable but a constant. Every participant will use the same books to make sure there is no variation. The books will be extended with arms out at 90 degree angles to the torso and the counting will begin when the elbows for the participants lock. Upon any bend in the elbows or lessening of the angle of the books to the mid-section (adduction) then the time trial will stop. After Trial 1 the participant gets 30 seconds of rest followed by Trial 2 and will repeat this process until the conclusion of Trial 3.

Independent variable

The independent variable is time here, recorded in seconds? Time will be recorded in seconds for as long the participants palms are up, holding the books, elbows locked, and arm in relation to the torso by 90 degrees. The participants will use their phones' stop watch features to record the time specifically

Dependent variables

The dependent variable are the participants themselves. More specifically their individual shoulder strength (muscle endurance) to maintain the proper posture needed of the experiment. Varying participants will complete the same procedure for three trials. The variable will be that multiple participants will conduct the experiment in hopes of obtaining a visible trend with muscle endurance relative to time.

Series

This experiment will study the muscle endurance (dependent variable) as a function of time (independent variable) of varying participants, the students themselves (series.)

Constants and Controls

The constants will be the temperature of the room. The fact that no one will have time to warm up or "prepare" in any other way to possibly sway the results in their favor will also be a constant. Everyone will receive 3 trials and a rest of 30 seconds in between. The angles that are to be expected are 180 degrees at the elbow (or as close to it based on the individuals flexibility) and 90 degrees at the armpit (where the torso meets the arm). The individual timer must be the same person that times all three trails so as to not gain or lose an advantage based on individual reflexes.

The control will be that the participants will be varied. Different heights, weights, genders, ethnicities, and body compositions will be tested blindly. Anyone can participate. Once again the main point of the experiment to test muscle endurance against time. In the future one could vary the experiment but that will not be done here.

Materials

The materials for this experiment are rather simple. I recommend using a "class set" of books so that you don't have to go out and purchase books that all weigh the same. Take whatever set of books you have (assuming that all weigh the same weight give or take a few grams) and make sure your students are present and ready to participate. With cell phones being so abundant you can easily use the stopwatch feature on your phone, download a free stopwatch app, or just use a good old fashioned stop watch. Whatever the means you have most of your students will have phone. If not you can easily purchase stopwatches at your nearest sporting goods store or purchase them online. They are relatively cheap and abundant.

Procedures

1) Make sure students are paired up. Student A and Student B.

2) Student A will go first with the books and Student B will time.

3) Upon verbal confirmation from B being ready A will raise their arms to the 90 degree and 180 angles specified with palms up and one book in each hand.

4) Upon the desired angles being hit by Student A, Student B will hit the start button and monitor the duration that A can keep the angles steady before breaking the angles and thus ending that specific trial.

5) The time (if longer than 1 minute) will be converted into seconds and recorded in the form provided.

6) Student A will get 30 seconds of rest.

7) When the rest cycle has finished trial number 2 begins in the same fashion that trial 1 was conducted.

8) The process will be repeated by Student A and B until the end of trial 3.

9) Make sure all the data for Student A has been "submitted" in the Google Form provided

10) At this point Student A and B will switch roles and continue the experiment following these procedures until the conclusion of trial 3 for Student B.

11) Once again make sure all data has been input into the Google Form and the experiment is complete. Data analysis can ensue when all the groups have entered their data.

Sample data and graphs

Muscle Endurance Form

Muscle Endurance Data (with Graphs)

Analysis & Conclusions

The experiment's hypothesis asks "How does endurance of muscle groups change with time?" The result is that there is a rather consistent drop off between the use of the muscle group initially and then the ability to keep using that muscle group in the same manner for the same amount of time. The results found that despite a few outliers (perhaps due to not nimble enough fingers tapping a stopwatch, or just the mustered spite to beat their fellow students) the muscle gets fatigued from use in the isometric movement holding the books. Simply put, muscles get tired after use.

Photos

Control: Two Identical Books (same mass)

Starting Position

Movies

References

Bodybuilding.com Article on Muscle Endurance

General Fitness Website on Muscle Endurance

Sports Fitness Advisor