An efficient global optimization procedure is presented by using Taguchi's design of experiments (TDE) as a means for undertaking biomechanical studies that rely on experimentations. The proposed TDE is a systematic method of fractional factorial designs for conducting experiments with many independent variables. The approach can provide a step-by-step means for predicting the results of a comparative full factorial design only with a small number of tests. In this study a three-level, four-variable heel-toe running model, and a two-level, seven-variable bicycle example were examined to show the capability and robustness of TDE. In the process of the analysis, the orthogonal array and signal-to-noise ratio analysis of TDE were used to set up the trial conditions and analyze the results. It is shown that in the heel-toe running analyses the TDE successfully predicted the optimum sets of variables with 89% fewer trials than the full factorial design. The reduction in number of trials in the bicycle example is 94%. As a result, the use of TDE analysis to replace a full factorial analysis can considerably reduce the number of trials and still provide a useful outcome in many multifactor biomechanical studies.
Nenzi Wang and Yen-Hsiu Liu
Adam E. Jagodinsky, Christopher Wilburn, Nick Moore, John W. Fox, and Wendi H. Weimar
coordination variability would be more significantly diminished in individuals with CAI compared with healthy individuals and copers when an ankle brace is applied. Materials and Methods Research Design The study was a mixed factorial design including a between-participants factor of group (healthy, coper, and
J. Dru Marshall and Marcel Bouffard
The primary purpose of this study was to document the actual gross movement competencies, as measured by the Test of Gross Motor Development, in obese versus nonobese children. A 2 Gender (male, female) × 2 Groups (obese, nonobese) × 2 Age Categories (Grade 1, Grade 4) × 2 Programs (quality daily physical education [QDPE], non-QDPE) completely randomized factorial design was used. A significant three-way interaction effect (Group × Age × Program) was found for the Locomotor Skills subscale, such that the difference in movement competency in locomotor skills between obese and nonobese children increased as children got older if they did not receive QPDE. A significant main program effect was also found for the Object Control Skills subscale, with the QDPE children scoring higher than the non-QDPE children. It appears, then, that QDPE programs offer a “protective” effect for the development of locomotor skills in obese children. Implications of these findings are discussed.
Jeffery L. Huston, Michelle A. Sandrey, Mathew W. Lively, and Kevin Kotsko
There is limited information on the effect of dynamic fatiguing of the plantar flexors on joint-position sense (JPS).
To examine the effects of fatigue on JPS for ankle plantar flexion (PF) and dorsiflexion (DF).
A 2 × 2 factorial design.
20 healthy subjects (10 men, 10 women; age 21.75 ± 1.48 years).
The subjects were tested at 10° DF and 20° PF in the nonfatigued and fatigued conditions on a custom-built JPS device. To induce fatigue, subjects stood with both feet in the plantar-flexed position until they could no longer hold the posture.
Main Outcome Measures:
JPS absolute error was measured at 10° DF and 20° PF.
There was no significant main effect for condition, measurement, or interaction between condition and measurement.
With no difference between conditions, the main controller of conscious JPS of the lower extremity might be the tibialis anterior.
Karen S. Meaney, L. Kent Griffin, and Melanie A. Hart
This investigation examined the effect of model similarity on girls’ acquisition, retention, transfer, and transfer strategies of a novel motor task. Forty girls (mean age = 10 years) were randomly assigned to conditions in a 2 (model skill level) ✓ 2 (model sex) factorial design using four treatment groups: (a) male skilled, (b) male learning, (c) female skilled, and (d) female learning. Quantitative data were collected throughout all phases of the investigation. ANOVA results for transfer strategies revealed a significant main effect for model skill level and model sex. Participants observing a female model or a learning model transferred significantly more learning strategies than did participants observing a male or skilled model. After quantitative data collection, qualitative data were obtained via structured interviews and assessed through content analysis. Results from the interview analyses underscored the need to include models of similar sex, as well as learning models when instructing girls in motor skills.
Terry L. Rizzo
This study assessed the attitudes of physical educators (n = 194) toward teaching handicapped pupils in the regular class. The survey instrument used was the Physical Educators Attitude Toward Teaching the Handicapped (PEATH), which assesses teacher attitudes according to the type of handicapping condition (learning and physical) and grade level (K-3, 4-6, 7-8). A 2 × 3 randomized block factorial design and the Tukey (HSD) post hoc analysis were applied to the data. Results indicated that physical educators held more favorable attitudes toward teaching pupils with learning handicaps than those with physical handicaps. Furthermore, as grade level advanced from primary (K-3) to intermediate (4-6) and upper (7-8) grades, teacher attitudes became progressively less favorable.
Pascal Legrain, Fabienne d’Arripe-Longueville, and Christophe Gernigon
This study examined the potential benefits of a peer tutoring program for tutors in a physical learning setting. Gender differences were also explored. Thirty-two college-age males and females identified as novices in a French boxing task were assigned in a 2 × 2, Gender × Training Type: Physical Practice (PP) versus Physical Practice associated with Peer Tutoring (PT) factorial design. All the participants were given six 2-hr French boxing lessons. The PT program included 6 min of peer coaching per lesson. Results indicated that the PT program entailed higher scores in boxing performance form, selfefficacy, interest-enjoyment, and personally controllable causal attributions and lower scores in tension-pressure. Males reported more certain expectancies and displayed higher performance outcomes than did females. Results are discussed in relation to the educational psychology literature.
Gonzalo A. Bravo, Doyeon Won, and Mauricio Ferreira
Trade-offs in consumer choice become central to understanding how choice actually occurs. This study examines the trade-offs sport management students are willing to make in order to select the program of their choice. Sport management undergraduate students (N = 498) participated in a full-profile conjoint experiment asking them to rate 18 program-choice scenarios resulted from the factorial design of seven attributes and nineteen levels. Results at the aggregated level indicated that program environment was the most important attribute in choosing a sport management graduate program, followed by program reputation, graduate assistantship, cost/tuition, NCAA affiliation, program length, and location. Given these results, a sensitivity analysis illustrated that students were willing to make trade-offs among program characteristics, particularly pay more for a program with better reputation. Results from the current study are valuable and informative for sport management programs for setting market boundaries and selecting what to promote when advertising to attract prospective students.
Michelle A. Sandrey and Timothy E. Kent
There is limited information on fatigue of the evertors on frontal plane joint position sense (JPS).
To examine the effects of isokinetic concentric-eccentric fatigue of the evertors on frontal plane JPS of the ankle.
A 2 × 4 factorial design.
Patients or Other Participants:
40 male and female healthy subjects.
JPS was tested at 10° and 20° of inversion and 5° and 10° of eversion in a nonfatigued/fatigued condition. After fatigue of evertors was determined on an isokinetic device, post fatigue testing of JPS occurred.
Main Outcome Measures:
JPS absolute error (AE) for inversion and eversion.
Main effect for condition and angle were significant with pre/post fatigue. There were overestimation of angles postfatigue with AE greater at 20° of inversion (P = .003), followed by 10° of inversion (P < .001), 10° of eversion (P = .005), and 5° of eversion (P = .005).
When the ankle evertors were fatigued, the AE for JPS was significantly higher at all test angles.
Wan-Xiang Yao and Mark G. Fischman
This study investigated, in aiming movements, the conditions needed to produce a single movement and those needed to produce secondary submovements. Using a 2 × 2 (Temporal Constraint × Spatial Constraint) factorial design with repeated measures on both factors, subjects moved a stylus from a starting position to a target position 12 cm away. They participated in two testing sessions on consecutive days. The first session involved two nonrestrictive target (a set of crosshairs) conditions, moving to the target either within a goal of 400 ms (temporal-accuracy procedure) or within a minimum time (time-minimization procedure). In the second session the subjects performed two strict-target (circle) conditions, moving to the target either within a goal of 400 ms or within a minimum time. The results showed that the two strict-target conditions had a greater percentage of trials containing multiple-submovements than the two nonrestrictive target conditions, regardless of temporal requirements. Therefore, whether an aiming movement contains a single movement or multiple submovements may be a function of spatial constraints regardless of temporal constraints. It appears that with respect to the nature of the speed-accuracy tradeoff, spatial constraints are an important factor.