The milestones in the movement of the field away from emphasizing p values, and toward emphasizing effect size reporting, are reviewed. The primer also briefly introduces the effect size types and recommends a few effect size usage and interpretation guidelines that journals and authors should follow.
Oluwaseyi Osho, Oluwatoyosi Owoeye, and Susan Armijo-Olivo
, & Haines, 2013 ; Nyman & Victor, 2012 ; Simek, McPhate, & Haines 2012 ). To quantify the effectiveness of a FPEP, the effect size is particularly valuable; it allows relative comparison between the intervention and control groups in a randomized controlled trial (RCT) ( Robert, 2002 ). It is a simple way
Mark B. Andersen, Penny McCullagh, and Gabriel J. Wilson
Many of the measurements used in sport psychology research are arbitrary metrics, and researchers often cannot make the jump from scores on paper-and-pencil tests to what those scores actually mean in terms of real-world behaviors. Effect sizes for behavioral data are often interpretable, but the meaning of a small, medium, or large effect for an arbitrary metric is elusive. We reviewed all the issues in the 2005 volumes of the Journal of Sport and Exercise Psychology, The Sport Psychologist, and the Journal of Applied Sport Psychology to determine whether the arbitrary metrics used in sport psychology research were interpreted, or calibrated, against real-world variables. Of the 54 studies that used quantitative methods, 25 reported only paper-and-pencil arbitrary metrics with no connections to behavior or other real-world variables. Also, 44 of the 54 studies reported effect sizes, but only 7 studies, using both arbitrary and behavioral metrics, had calculated effect indicators and interpreted them in terms of real-world meaning.
Philippe Terrier and Fabienne Reynard
Local dynamic stability (stability) quantifies how a system responds to small perturbations. Several experimental and clinical findings have highlighted the association between gait stability and fall risk. Walking without shoes is known to slightly modify gait parameters. Barefoot walking may cause unusual sensory feedback to individuals accustomed to shod walking, and this may affect stability. The objective was therefore to compare the stability of shod and barefoot walking in healthy individuals and to analyze the intrasession repeatability. Forty participants traversed a 70 m indoor corridor wearing normal shoes in one trial and walking barefoot in a second trial. Trunk accelerations were recorded with a 3D-accelerometer attached to the lower back. The stability was computed using the finite-time maximal Lyapunov exponent method. Absolute agreement between the forward and backward paths was estimated with the intraclass correlation coefficient (ICC). Barefoot walking did not significantly modify the stability as compared with shod walking (average standardized effect size: +0.11). The intrasession repeatability was high (ICC: 0.73–0.81) and slightly higher in barefoot walking condition (ICC: 0.81–0.87). Therefore, it seems that barefoot walking can be used to evaluate stability without introducing a bias as compared with shod walking, and with a sufficient reliability.
Michele A. Parker and Bruce M. Gansneder
Column-editor : Michael G. Dolan
Poliana Alves de Oliveira, Juscelino Castro Blasczyk, Gerson Souza Junior, Karina Ferreira Lagoa, Milene Soares, Ricardo Jacó de Oliveira, Paulo José Barbosa Gutierres Filho, Rodrigo Luiz Carregaro, and Wagner Rodrigues Martins
Elastic Resistance Exercise (ERE) has already demonstrated its effectiveness in older adults and, when combined with the resistance generated by fixed loads, in adults. This review summarizes the effectiveness of ERE performed as isolated method on muscle strength and functional performance in healthy adults.
A database search was performed (MEDLine, Cochrane Library, PEDro and Web of Knowledge) to identify controlled clinical trials in English language. The mean difference (MD) with 95% confidence intervals (CIs) and overall effect size were calculated for all comparisons. The PEDro scale was used assess the methodological quality.
From the 93 articles identified by the search strategy, 5 met the inclusion criteria, in which 3 presented high quality (PEDro > 6). Meta-analyses demonstrated that the effects of ERE were superior when compared with passive control on functional performance and muscle strength. When compared with active controls, the effect of ERE was inferior on function performance and with similar effect on muscle strength.
ERE are effective to improve functional performance and muscle strength when compared with no intervention, in healthy adults. ERE are not superior to other methods of resistance training to improve functional performance and muscle strength in health adults.
Chunmei Cao, Yu Liu, Weimo Zhu, and Jiangjun Ma
Recently developed active workstation could become a potential means for worksite physical activity and wellness promotion. The aim of this review was to quantitatively examine the effectiveness of active workstation in energy expenditure and job performance.
The literature search was conducted in 6 databases (PubMed, SPORTDiscuss, Web of Science, ProQuest, ScienceDirect, and Scopuse) for articles published up to February 2014, from which a systematic review and meta-analysis was conducted.
The cumulative analysis for EE showed there was significant increase in EE using active workstation [mean effect size (MES): 1.47; 95% confidence interval (CI): 1.22 to 1.72, P < .0001]. Results from job performance indicated 2 findings: (1) active workstation did not affect selective attention, processing speed, speech quality, reading comprehension, interpretation and accuracy of transcription; and (2) it could decrease the efficiency of typing speed (MES: –0.55; CI: –0.88 to –0.21, P < .001) and mouse clicking (MES: –1.10; CI: –1.29 to –0.92, P < .001).
Active workstation could significantly increase daily PA and be potentially useful in reducing workplace sedentariness. Although some parts of job performance were significantly lower, others were not. As a result there was little effect on real-life work productivity if we made a good arrangement of job tasks.
Abbas Asadi, Hamid Arazi, Warren B. Young, and Eduardo Sáez de Villarreal
To show a clear picture about the possible variables of enhancements of change-of-direction (COD) ability using longitudinal plyometric-training (PT) studies and determine specific factors that influence the training effects.
A computerized search was performed, and 24 articles with a total of 46 effect sizes (ESs) in an experimental group and 25 ESs in a control group were reviewed to analyze the role of various factors on the impact of PT on COD performance.
The results showed that participants with good fitness levels obtained greater improvements in COD performance (P < .05), and basketball players gained more benefits of PT than other athletes. Also, men obtained COD results similar to those of women after PT. In relation to the variables of PT design, it appears that 7 wk (with 2 sessions/wk) using moderate intensity and 100 jumps per training session with a 72-h rest interval tends to improve COD ability. Performing PT with a combination of different types of plyometric exercises such as drop jumps + vertical jumps + standing long jumps is better than 1 form of exercise.
It is apparent that PT can be effective at improving COD ability. The loading parameters are essential for exercise professionals, coaches, and strength and conditioning professionals with regard to the most appropriate dose-response trends to optimize plyometric-induced COD-ability gains.
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.
Dai Sugimoto, Jessica C. LeBlanc, Sarah E. Wooley, Lyle J. Micheli, and Dennis E. Kramer
It is estimated that approximately 350,000 individuals undergo anterior cruciate ligament (ACL) reconstruction surgery in each year in the US. Although ACL-reconstruction surgery and postoperative rehabilitation are successfully completed, deficits in postural control remain prevalent in ACL-reconstructed individuals. In order to assist the lack of balance ability and reduce the risk of retear of the reconstructed ACL, physicians often provide a functional knee brace on the patients’ return to physical activity. However, it is not known whether use of the functional knee brace enhances knee-joint position sense in individuals with ACL reconstruction. Thus, the effect of a functional knee brace on knee-joint position sense in an ACL-reconstructed population needs be critically appraised. After systematically review of previously published literature, 3 studies that investigated the effect of a functional knee brace in ACL-reconstructed individuals using joint-position-sense measures were found. They were rated as level 2b evidence in the Centre of Evidence Based Medicine Level of Evidence chart. Synthesis of the reviewed studies indicated inconsistent evidence of a functional knee brace on joint-position improvement after ACL reconstruction. More research is needed to provide sufficient evidence on the effect of a functional knee brace on joint-position sense after ACL reconstruction. Future studies need to measure joint-position sense in closed-kinetic-chain fashion since ACL injury usually occurs under weight-bearing conditions.