Critiques: How do you plan on mesuring muscle size because muscle doesn't develope over night and some people already have more then others before you started. (Meryl) Good point! - what about measuring improvement in muscle size over the course of the experiment? (Stoller)
Do you have a workout planned for your test subjects to do(klekamp) How are you going to make this equal? If you were to make the weights the same and lets say that was the max the girl could lift but the boy could lift more, that wouldn't be working their muscles in the same way.(Audrey)
Are you going to test a boy and a girl that have the same muscle size because if not than this experiment would be invalid because of one having already bigger muscles than the other. (Riley Wagner)
Should test more people. (Josh P)
What if the experimental people are physically unable to do the experiment?(Howard Lin)
Would the people being tested be eating the same amount/type of food? The amount of protein could have an effect on muscle growth.(Hailey Avis)
What if they excersize outside of the experiment? that could change your results too. (Mariah Moore)
first you have to find out how fast boys muscles increase(devin Donigian)
Are they going to be working out the EXACT same way or is technique/strength going to affect your experiment? Are other factors going to affect the experiment, like carrying a heavy backpack or track practice,etc.?

Muscle Increase in Females and Males

Question: Does Muscle and Body Fat Percent Increase and Decrease Faster in Females or Males?

Independent Variable: Exercise by doing bicep curls, and twisting hammer curl.

Dependent Variable: Increase in size, and change in caliper fat.

Hypothesis: If males and females lift dumbbells for five weeks then the male's bicep muscle will have increased more and their caliper fat will have decreased more also.


- Humans
- Dumbbells
- Tape Measurer
- Caliper


(For procedures 1-3 measure both the right arm and the left)

1. Measure the highest point of the bicep and the lowest point of the tricep of the bicep while it is flexed to get the circumference. Use with a tape measurer.

2. Measure in between the elbow and shoulder and at the center of the back of the arm to get the body fat percentage on the tricep using the caliper.

3. Lift the _lbs dumbbells every day for five weeks.

4. Workout

a. Lift by holding lefthand dumbbell at a 90° angle while right arm does reps of 7 then switch arms so the righthand dumbbell is at a 90° angle and the left arm does 7 reps. Do this until you cannot anymore.

b. Start by having your palms facing your torso while holding the dumbbells and then slowly bring it up so your ending point is about your fist infront of the bottom or middle of your neck, and then bring it back down. Then do your left arm repeating the same as the right. Do this until you cannot do anymore.

c. Start by sitting on a chair, and then take one dumbbell and have it start on your shoulder to have a easier start. Then use both hands and hold the dumbbell behind your head with the bottom of the dumbbell at the top of your head. Then go up and down. Do this until you cannot anymore.

5. Only workout Monday-Friday. Take weekends off.

6. Repeat steps 1-3.

Data Table:

Original size of the right bicep
Original size of the left bicep
Original amount of body Fat% in the right tricep
Original amount of body Fat% in the left tricep
After size of the right bicep
After size of the left bicep
After amount of body fat% in right tricep
After amount of body fat% in left tricep
13 ¼”
Sarah Beth
11 ½”
11 ¼”
11 ¾”
11 ¼”


After five weeks of a specific workout huge changes were seen, but not changes that you could see by just looking. Ethan started out with a bicep size of 13" while flexed for his right bicep and 13" also for his left bicep. Sarah Beth did not start with as big of muscles, but she started out with 11 1/2" while flexed for her right bicep and 11 1/4" for her left bicep. These numbers seemed pretty big and it was very interesting at the end of the five weeks to remeasure the biceps. At the end of five weeks Ethan and Sarah Beth's bicpes were remeasured. Ethan's right bicep increased in size by a 1/4". That was quite an improvement for not a super difficult workout. However, his left bicep did not change any. As for Sarah Beth, her right bicep increased also a 1/4", and also like Ethan her left bicep did not increase by size any. Although even though the left bicep did not increase in size for either of the test subjects, their biceps did not decrease in size. At the beginning of the five weeks Ethan's and Sarah Beth's body fat percent in their triceps were also measured by a caliper to see if their Body Fat Percent (BFP) would decrease with this workout. In the begining Ethan started out with a 1/2" of BFP in his right tricep, and his left tricep was the same, 1/2". Sarah Beth's BFP was also measured, and was 3/4" of BFP in her right tricep and left tricep. After the five weeks were over again when we measured their bicep size we also remeasured their Body Fat Percent (BFP). Ethan's right BFP changed dramatically of a half of an inch. It went from 1/2" to 1/4" which is a lot for his BFP. His left tricep didn't change any, and stayed at the same 1/2". Sarah Beth's BFP did not change in either tricep and stayed at 3/4".

If males and females lift dumbbells for five weeks then the male's muscle will have increased more and their caliper fat will have decreased more also. With these five weeks of workouts and the two days of measuring, at the beginning and end. Many changes were seen and they were very intruging changes. Ethan's bicep size remained mainly constant other than his right arm, and so did Sarah Beth's. However, Ethan's Body Fat Percent decreased much more unlike Sarah Beth's. It seems like muscle increased about the same for both test subjects however male body fat percent seemed to decrease faster than female's. So in the end, the hypthesis, if males and females lift dumbbells for five weeks then the male's muscle will have increased more and their caliper fat will have decreased more also, was both correct and incorrect because the caliper fat in males did decrease more, but the male's and female's muscle both increased at a gradual rate. To be able to prove this better it would be best to get many more test subjects of both male and females, and also have the workout last longer than five weeks for more conclusive data. Another downside to this expermiment was the age difference between the two test subjects. Ethan (16) and Sarah Beth (15) could have an affect on how much more Ethan can grow, and if Sarah Beth can much more too. Many uncontrollable factors with this experiment made it not the most conclusive experiment, but in the end it does seem like males caliper fat decreases faster than a females, and also that males and females bicep muscle size increases at the same rate.


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"General Philosophies of Muscle Mass Gain | BodyRecomposition - The Home of Lyle McDonald." Lyle McDonald - Bodyrecomposition. Ed. Body Recomposition. Web. 14 Feb. 2012. <>.

Westcott, Wayne L. "Men vs. Women - Muscle, Strength, Exercise." JaxTrainer - Jacksonville FL. Certified Advanced Personal Trainer, Rossiter Coach, Private Sessions. 2007. Web. 14 Feb. 2012.

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