ABSTRACT
CONTEXT: The Dynavision D2™ Mode A test (ModeA) is a 1-minute reaction time (RT) test commonly used in sports science research and clinical rehabilitation. However, there is limited data regarding the effect of repeated testing (ie, training) or subsequent periods of no testing (ie, detraining) on test-retest reliability and RT performance. Therefore, the purpose of this study was to examine the test-retest reliability, training, and detraining effects associated with the D2™ ModeA test. DESIGN: Repeated measures/reliability. METHODS: Twenty-four recreationally active men and women completed 15 training sessions consisting of 2 ModeA tests per session (30 tests). The participants were then randomized to either 1 or 2 weeks of detraining prior to completing 15 retraining sessions (30 tests). The training and retraining periods were separated into 10 blocks for analysis (3 tests per block). The number of hits (hits) and the average RT per hit (AvgRT) within each block were used to determine RT performance. Intraclass correlation coefficients, SEM, and minimum difference were used to determine reliability. Repeated-measures analysis of variance/analysis of covariance were used to determine training and detraining effects, respectively. RESULTS: The ModeA variables demonstrated excellent test-retest reliability (intraclass correlation coefficient2,3 > .93). Significant improvements in hits and AvgRT were noted within training blocks 1 to 5 (P < .05). No further improvements in RT performance were noted between training blocks 6 through 10. There was no effect of detraining period on RT. The RT performance was not different between blocks during retraining. CONCLUSIONS: It appears that 15 tests are necessary to overcome the training effect and establish reliable baseline performance for the ModeA test. Detraining for 1 to 2 weeks did not impact RT performance. The authors recommend that investigators and clinicians utilize the average of 3 tests when assessing RT performance using the D2 ModeA test.
Subject(s)
Reaction Time , Female , Humans , Male , Reproducibility of ResultsABSTRACT
Ultrasonography of the lower body typically encompasses supine rest due to fluid shifts affecting tissue size and composition. However, vastus lateralis (VL) examination is completed in the lateral recumbent position, and this positional change may influence morphology and its ability to predict function. This study aimed to examine the effect of position on VL morphology and its relationship with lower-body performance. Cross-sectional area (CSA), muscle thickness (MT), pennation angle (PA), echo intensity (UnCorEI), subcutaneous adipose tissue thickness (SFT), and echo intensity corrected for SFT (CorEI) were assessed in 31 resistance-trained males (23.0 ± 2.1 yrs; 1.79 ± 0.08 m; 87.4 ± 11.7 kg) immediately after transitioning from standing to supine (IP), after 15 min of standing (ST), and after 15 min of rest in three recumbent positions: supine (SUP), dominant lateral recumbent (DLR), non-dominant lateral recumbent (NDLR). Participants also completed unilateral vertical jumps, isometric/isokinetic tests, and a one-repetition maximum leg press. CSA, MT, PA, and SFT were greater in ST compared to NDLR, DLR, and SUP (p < 0.05). CSA, UnCorEI, and CorEI were different between recumbent positions; however no differences were observed for MT, PA, and SFT. Different magnitudes of relationships were observed between muscle morphological characteristics measured after rest in different positions and performance variables. Muscle morphology in IP generally appears to be the best predictor of performance for most variables, although utilizing the NDLR and DLR positions may provide comparable results, whereas morphology measured in ST and SUP provide weaker relationships with physical performance. IP also requires less time and fewer requirements on the technician and subject, thus researchers should consider this positioning for VL examination.
