% confidence intervals, and intraclass correlation coefficient (ICC 2, k ) 11 were calculated as measures of reliability. An ICC greater than .8 and a CV less than 10% were considered to exhibit acceptable reliability in this study. 12 , 13 The smallest worthwhile change represented the sensitivity of each
Simon A. Feros, Warren B. Young, and Brendan J. O’Brien
Rob Buck and Michael Ian Lambert
measurement and the smallest worthwhile change (SWC) ( 16 ). If the TE is greater than the SWC the measurement will only be able to detect large changes. Conversely, small changes will be detected if the TE is lower than the SWC. This approach is well established in high performance sport ( 26 ) and should be
Corbin Griffen, David Rogerson, Mayur Ranchordas, and Alan Ruddock
This study investigated the effects of creatine and sodium bicarbonate coingestion on mechanical power during repeated sprints. Nine well-trained men (age = 21.6 ± 0.9 yr, stature = 1.82 ± 0.05 m, body mass = 80.1 ± 12.8 kg) participated in a double-blind, placebo-controlled, counterbalanced, crossover study using six 10-s repeated Wingate tests. Participants ingested either a placebo (0.5 g·kg−1 of maltodextrin), 20 g·d−1 of creatine monohydrate + placebo, 0.3 g·kg−1 of sodium bicarbonate + placebo, or coingestion + placebo for 7 days, with a 7-day washout between conditions. Participants were randomized into two groups with a differential counterbalanced order. Creatine conditions were ordered first and last. Indices of mechanical power output (W), total work (J) and fatigue index (W·s−1) were measured during each test and analyzed using the magnitude of differences between groups in relation to the smallest worthwhile change in performance. Compared with placebo, both creatine (effect size (ES) = 0.37-0.83) and sodium bicarbonate (ES = 0.22-0.46) reported meaningful improvements on indices of mechanical power output. Coingestion provided small meaningful improvements on indices of mechanical power output (W) compared with sodium bicarbonate (ES = 0.28-0.41), but not when compared with creatine (ES = -0.21-0.14). Coingestion provided a small meaningful improvement in total work (J; ES = 0.24) compared with creatine. Fatigue index (W·s−1) was impaired in all conditions compared with placebo. In conclusion, there was no meaningful additive effect of creatine and sodium bicarbonate coingestion on mechanical power during repeated sprints.
Kristie-Lee Taylor, John Cronin, Nicholas D. Gill, Dale W. Chapman, and Jeremy Sheppard
This investigation aimed to quantify the typical variation for kinetic and kinematic variables measured during loaded jump squats.
Thirteen professional athletes performed six maximal effort countermovement jumps on four occasions. Testing occurred over 2 d, twice per day (8 AM and 2 PM) separated by 7 d, with the same procedures replicated on each occasion. Jump height, peak power (PP), relative peak power (RPP), mean power (MP), peak velocity (PV), peak force (PF), mean force (MF), and peak rate of force development (RFD) measurements were obtained from a linear optical encoder attached to a 40 kg barbell.
A diurnal variation in performance was observed with afternoon values displaying an average increase of 1.5–5.6% for PP, RPP, MP, PV, PF, and MF when compared with morning values (effect sizes ranging from 0.2–0.5). Day to day reliability was estimated by comparing the morning trials (AM reliability) and the afternoon trials (PM reliability). In both AM and PM conditions, all variables except RFD demonstrated coefficients of variations ranging between 0.8–6.2%. However, for a number of variables (RPP, MP, PV and height), AM reliability was substantially better than PM. PF and MF were the only variables to exhibit a coefficient of variation less than the smallest worthwhile change in both conditions.
Results suggest that power output and associated variables exhibit a diurnal rhythm, with improved performance in the afternoon. Morning testing may be preferable when practitioners are seeking to conduct regular monitoring of an athlete’s performance due to smaller variability.
Joel M. Garrett, Stuart R. Graham, Roger G. Eston, Darren J. Burgess, Lachlan J. Garrett, John Jakeman, and Kevin Norton
smallest worthwhile change (SWC) is regarded as the smallest worthwhile change in frequency outside of the expected measurement error and the minimum change in performance required to be of meaningful consequence. 1 , 3 , 4 Consequently, it provides information on whether the change observed is “real” or
Antonio Dello Iacono, Stephanie Valentin, Mark Sanderson, and Israel Halperin
–Altman bias estimates. Finally, sensitivity of the PF outputs obtained from the strain gauge and force plate was assessed by comparing the smallest worthwhile change (SWC) and standard error of measurement (SEM), and interpreted using the thresholds proposed by Liow and Hopkins. 15 Statistical significance
Thomas M. Comyns, Eamonn P. Flanagan, Sean Fleming, Evan Fitzgerald, and Damian J. Harper
usefulness of the 10/5 RJT test for detecting the smallest worthwhile change (SWC) was not evaluated. Given the potential for rebound RSI jump performance to monitor changes in ankle joint stiffness particularly in the eccentric phase, 16 the capacity to sustain high eccentric muscle activity or reactive
Rodrigo Rodrigues Gomes Costa, Jefferson Rodrigues Dorneles, Guilherme Henrique Lopes, José Irineu Gorla, and Frederico Ribeiro Neto
smallest worthwhile change (SWC) is a metric used to determine the smallest difference that can lead to a meaningful change in the performance of an individual or team sport. 6 In this way, the present study aimed to test the MBT responsiveness to detect meaningful changes after WB training sessions in
Samuel Ryan, Thomas Kempton, Emidio Pacecca, and Aaron J. Coutts
) was collected for the left and right limbs of each player in addition to the combined force of both limbs divided by 2. The intrarater reliability of the test was assessed using Hopkins reliability spreadsheets, 10 calculating a coefficient of variation (CV) and smallest worthwhile change (SWC). Week
Kolbjørn Lindberg, Paul Solberg, Thomas Bjørnsen, Christian Helland, Bent Rønnestad, Martin Thorsen Frank, Thomas Haugen, Sindre Østerås, Morten Kristoffersen, Magnus Midttun, Fredrik Sæland, Ingrid Eythorsdottir, and Gøran Paulsen
smallest worthwhile change (SWC) can be estimated by multiplying the baseline SD of the sample by 0.2 (a small effect size). 7 From this, the SWC in relation to the TE (SWC:TE) represents the signal-to-noise ratio, which should preferably be greater than one. 20 This approach has only recently been