Formulating the Method KNES 510 Research Methods in Kinesiology 1 Planning the Methods Parts of the method section Participants Instruments or apparatus Procedures Design and analysis Two principles of planning Less is more. Simple is better. 2 Describing Participants Special characteristics: what relates to the study? Age, HT, mass and sex Training level What to tell about participants Number Loss of participants Protecting participants (see chapter 5) 3 Participants - Proposal For this study 48 males, ranging in age from 21 to 34 years, will be randomly selected from a group (N = 147) of welltrained distance runners (VO2 max = 60 ml/kg/min or higher) who have been competitive runners for at least 2 years. Participants will be randomly assigned to one of four groups (n = 12). 4 Participants - Defense In this study 48 males, ranging in age from 21 to 34 years, were randomly selected from a group (N = 147) of well-trained distance runners (VO2 max = 60 ml/kg/min or higher) who had been competitive runners for at least 2 years. The participants had the following characteristics (standard deviations in parentheses): age, 26 years (3.3); height, 172.5 cm (7.5); weight, 66.9 kg (8.7); and VO2 max, 65 ml/kg/min (4.2). Participants were randomly assigned to one of four groups (n = 12). 5 Describing Instruments Questions to consider in selecting instruments Validity and reliability Difficulty of obtaining measures Access to equipment or tests Knowing how to use them What should be presented Description (including validity and reliability) Drawing, photograph, sample items How it is scored 6 Describing Procedures What will happen When, where, how much time Pilot data: can you do this? Scheme for data acquisition, recording, and scoring Planning treatments How long, how intense, how often Participant adherence Pilot data: can participants do this? Appropriate treatment for participants 7 Avoiding Methodological Faults Details of the procedures Specific order of things Timing of events Instructions given Briefings, debriefings, safeguards Piloting your procedures Can you do this? Can participants do this? Do measures work? Do treatments work? 8 Example – Methods Subjects Thirty adult subjects between the ages of 19 and 29 years of age will volunteer for this study. The subjects will be randomly assigned to one of three groups: 1) control group (n = 10); 2) slow velocity training group (n = 10); or 3) fast velocity training group (n = 10). The study will require two (control group) or five (slow velocity and fast velocity training groups) visits, lasting approximately one hour per visit. 9 Example – Methods, cont’d. All subjects will be tested on visits 1 and 5, and the two training groups will train on visits 2, 3, and 4. There will be 48-72 hours between testing and/or training sessions. 10 Testing/Training Schedule 11 Example – Methods, cont’d. Strength Testing Following a five-minute warm-up, subjects will perform three maximal, concentric isokinetic muscle actions of the leg extensors of the nondominant leg on a Cybex II dynamometer (Cybex, Inc., Ronkonkoma NY) The tested velocities will be 30, 150, and 270.s-1. The order of testing velocities will be randomized. The intraclass reliability coefficient for isokinetic PT is R = 0.959. 12 Example – Methods, cont’d. Training Protocol The training groups will perform slow velocity (30.s-1) or fast velocity (270.s-1) isokinetic leg extensions. The subjects in each training group will perform four sets of 10 maximal muscle actions at their respective velocities on visits 2, 3, and 4. 13 Example – Methods, cont’d. Electromyographic Measurements Three separate bipolar (20 mm center-tocenter) surface electrode (circular 4 mm diameter Ag-AgCl, Biopac Systems, Inc., Santa Barbara, CA) arrangements will be placed over the longitudinal axes of the vastus lateralis, rectus femoris, and vastus medialis muscles. Intraclass reliability coefficients for electromyographic measures from the superficial quadriceps femoris range from R = 0.80 to 0.88. 14 Example – Methods, cont’d. Mechanomyographic Measurements The MMG signal will be detected by accelerometers (Entran, EGAS-FT-10-/V05, Hampton, VA). The accelerometers will be placed over the bellies of the vastus lateralis, rectus femoris, and vastus medialis muscles between the active EMG electrodes. Intraclass reliability of mechanomyographic signals range from R = 097 to 0.98. 15 16 Example – Methods, cont’d. Signal Processing The sampling frequency will be 1000 Hz for all signals. The EMG and MMG signals will be bandpass filtered (fourth-order Butterworth filter) at 5100 Hz and 10-500 Hz, respectively. 17 Example – Methods, cont’d. The EMG and MMG amplitude and frequency values will be calculated for a time period that corresponds to a 50 range of motion from approximately 110 to 160 of leg flexion (i.e., at 30.s-1 the amplitudes and frequencies for 1.67 s of the MMG and EMG signals will be calculated, at 150.s-1 the amplitudes and frequencies for 0.33 s will be calculated, and at 270.s-1 the amplitudes and frequencies for 0.19 s will be calculated) . 18 Example – Methods, cont’d. Signal Processing, cont’d. The amplitude of the signals will be expressed as root mean square (rms) amplitude values. All frequency analyses will be performed with custom programs written with Labview software (version 6.1, National Instruments, Austin, Texas) and expressed as hertz (Hz). Frequency data will be expressed as mean power frequency (MPF). 19 Design and Analysis Design a study in which the treatments cause the changes observed the variables are related with no intervening variables 20 Design and Analysis, cont’d Analyzing the data Correct analysis Correct interpretation Establishing cause and effect Independent variable dependent variable 21 Data Analysis Example Statistical Analyses Isokinetic PT data will be analyzed using a 3-way (or a 3 x 2 x 3) (velocity [30, 150, and 270.s-1] time [pretraining, posttraining] group [slow velocity, fast velocity, control]) mixed factorial ANOVA. EMG and MMG data will be analyzed using 4-way (muscle [vastus lateralis, rectus femoris, vastus medialis] velocity [30, 150, and 270.s-1] time [pretraining, posttraining] group [slow velocity, fast velocity, control]) mixed factorial ANOVAs. An a-priori alpha of 0.05 will be considered significant for all comparisons. 22 Methodological Characteristics Influence Each Other Interactions among participants and measurements participants and treatments measurements and treatments participants, measurements, and treatments 23 Next Class Midterm Exam Chapter 19 Write (due the week after midterm): First draft of methods First sub-heading of lit review complete 24