Methods
Twelve participants will be participating in this study; chosen from all different backgrounds with varying levels of athleticism and participation in athletic activities. All the participants were informed that they need to create a playlist of music that they considered to be motivation, but otherwise performed the experiment primarily blind as to not create a bias. The chosen participants came into the laboratory twice to fulfill the experiment, one day they completed the tasks without music and the second time they used a playlist of self-selected music. The participants were selected at random to perform the tests with music on the first day, and some were asked to perform the tasks with no music on the first day in order to keep other confounding variables out of the experiment. Three participants would serve as the control group and would perform all of the experiments twice with no music either time. In order to eliminate the confound of previous muscular fatigue or delayed-onset muscle soreness, the subjects came in 4 days apart from each experiment. The participation pool was not limited by gender or age, in order to record a more representative pool of data regarding the impact of music upon muscular fatigue across all categories. Unfortunately, the sample size was limited due to a lack of time.
Heart rate can easily be measured on the ECG, but heart rate variability was a separate metric that had to be extracted from the ECG readings and is a good indicator of the autonomic nervous system's balancing act of the sympathetic and parasympathetic branch activation. The method of analyzing heart rate variability used was a frequency domain analysis, which ultimately determines how much of a recorded signal lies within standardized frequency ranges. In terms of heart rate variability, each of the two frequency ranges represents a specific physiological phenomenon. The two most commonly used metrics for this are high frequency (HF) which represents signals of the .15-.40 Hz range, and low frequency (LF) which represents signals of the 0.04-.15 Hz range. In our study, we only analyzed LF values as this is indicative of sympathetic branch activation, and we are interested in seeing the fluctuation of the sympathetic branch in response to music. The parasympathetic branch does not play a prominent role when it comes to working out and resistance training.
Data from the EMG recording was processed using the root mean square method, which is used to analyze the raw EMG signal of isometric voluntary muscle contraction. Ultimately, this method greatly smooths out individual spikes seen in the EMG recording and allows for much more clear indication of change in activity of the muscle over time.
Procedure 1: ECG Recording (heart rate variability) -
The participant was prepared for ECG, and the recording was taken as outlined in the protocol for laboratory experiment #5. The volunteer should be instructed to relax for a minute while not listening to music, and their ECG trace will be recorded. When the volunteer returns a minimum of one day later for a conduction of the experimental protocol, under the same conditions. However, this time the individual will be instructed to listen to their music of choice for a minute before recording, and then for the minute of recording. The particular phenomenon of interest for this recording would be heart rate variability. Heart rate variability is defined as the time interval between beats. Heart rate would also be calculated for the music and non-music group, which is done by counting the number of QRS complexes in a 15 second period, and multiplying this number by four.
Procedure 1: ECG Recording (heart rate variability) -
The participant was prepared for ECG, and the recording was taken as outlined in the protocol for laboratory experiment #5. The volunteer should be instructed to relax for a minute while not listening to music, and their ECG trace will be recorded. When the volunteer returns four days later for the second half of the experiment they will again be instructed to relax, but instead will be allowed to listen to their music of choice for a minute before recording and then for the minute of recording. The particular phenomenon of interest for this recording would be heart rate variability. Heart rate variability is defined as the time interval between beats. Heart rate would also be calculated for the music and non-music group, which is done by counting the number of QRS complexes in a 15 second period, and multiplying this number by four.
Procedure 2: Goniometer -
The participant was prepared to use the goniometer, and the recording was taken as outlined in the protocol for laboratory experiment #2. The goniometer was placed over the elbow joint. In this exercise, the volunteer is asked to perform a bicep curl. Prior to data collection, a baseline angle should be obtained by having the subject complete a partial bicep contraction, maintaining a 90 degree angle between the forearm/arm. The researcher will time the individual (in seconds) under exposure to music/no music to see how long the subject can sustain the starting position of a 90 degree bicep curl contraction. The subject will be timed until there is a 10-degree difference in forearm/arm angle orientation while using a 10 pound dumbbell to offer resistance.
Procedure 3: Hand Dynamometer -
Volunteer picks up and loosely grips hand dynamometer in a fist of the dominant hand. The subject is exposed to the music for a minute of their choice prior to beginning the exercise. The volunteer will be asked to grip the dynamometer at maximum strength for 3 seconds in order to get a 100% baseline. The subject is then instructed to grip the dynamometer for 20 seconds at 60, 80 and 100% maximal grip strength. (If a volunteer is not instructed to listen to music prior to running experiment, then they will simply perform the trial accordingly). What will be recorded is the time that they are able to stay within a 4% range (as indicated in lab protocol 3) of the intended percentage of their maximal grip strength. This procedure tests for possible increase in motor skills when exposed to music, considering that certain rhythms may allow for the individual to stay within the desired range more accurately. Music can also serve to distract the subject from the fatigue associated with prolonging their maximum grip strength at to remain within the desired range (REWORD??). The maximum force of grip strength, as well as the duration of maximum, will be averaged between the control and experimental groups.
Procedure 4: EMG -
Volunteer was prepared for EMG by skin abrasion and electrode gel placed on earth electrode wristband, the reading was taken as outlined in the protocol used in laboratory experiment #4. Now the volunteer is explicitly faced away from the monitor and be instructed to hold 5, 10, 15 pound weights, respectively. Subject is instructed to place elbow on table and simply lift the weight as if they were performing a bicep curl. They are instructed to not flex their muscle while performing the task, but rather simply life the weight. Subject will lift each weight twice, with a brief pause between each curl as instructed by the researcher. Data should be recorded throughout the entirety of the test run. When the volunteer returns again they will be instructed to listen to the songs of their choosing and the same process of lifting the weight toward the body will be repeated.
Statistical analysis
Results
Effects of music on Amplitude of Hand Grip Strength (Hand dynamometer)
Effects of music on Heart Rate (ECG)
Effects of music on Angle Sustenance under Weighted Bicep Curl (Goniometer)
Effects of music on Amplitude of Muscle Contraction (EMG)