Intra and intersession reliability of balance measures during one-leg standing in young adults

A study was designed to investigate the intra and intersession reliability during 1-leg standing recorded from a computerized balance platform. Thirty-nine healthy young men (n = 17, age range: 20-30 years) and women (n = 22, age range: 21-28 years) performed 3 testing sessions, with the second session 30 minutes (intrasession comparison) and the third session 1 week (intersession comparison) after the initial testing session. Within each testing session, participants completed 3 trials of 1-leg standing with their dominant leg. Reliability statistics were calculated using the mean of all 3 trials during each session for 6 balance measures (i.e., total displacements of the center of pressure [CoP], the CoP displacements in mediolateral and anterior-posterior directions, and the CoP speed and CoP area and their SD). Test-retest reliability was examined calculating both, intraclass correlation coefficient (ICC) with 95% confidence interval (95% CI) and Bland-Altman plots. In both sexes and irrespective of balance measure, ICC values were ≥0.75 except for 1 parameter in men. This indicates an excellent intra and intersession reliability. Bland-Altman plots confirmed these findings by showing that only 1 or 2 (4.5-11.8%) of the data points were beyond the 95% CI. Practitioners and clinicians are provided with a posturographic test setup that proved to be reliable. Researchers can use these data to identify the range in which the true value of a subject's score lies and estimate a priori sample sizes.     

Reliability of Infrared Plethysmography in BVP Biofeedback Therapy and the Relevance for Clinical Application

Biofeedback methods are well established as behavioral techniques for the therapy of various psychophysiological diseases. The forms of feedback generally employed are muscle activity (electromyogram), skin temperature, brain activity (electroencephalogram), and vasomotoricity. The latter technique, which employs plethysmographic feedback, has been studied most extensively in the therapy of migraine (vasoconstriction training, blood volume pulse training). Although the clinical efficacy has been demonstrated in several studies, little is known about the psychometric properties of this technique. This study examined the intrasession and intersession reliability of the pulse volume amplitude (PVA). The results showed that the PVA measurements within a single biofeedback session were highly reliable. Repositioning of the probe within the session resulted in a lower correlation coefficient, but one that was still sizable and significant. The PVA values from different sessions were not reliable (or comparable).     

The reliability of three devices used for measuring vertical jump height

The purpose of this investigation was to assess the intrasession and intersession reliability of the Vertec, Just Jump System, and Myotest for measuring countermovement vertical jump (CMJ) height. Forty male and 39 female university students completed 3 maximal-effort CMJs during 2 testing sessions, which were separated by 24-48 hours. The height of the CMJ was measured from all 3 devices simultaneously. Systematic error, relative reliability, absolute reliability, and heteroscedasticity were assessed for each device. Systematic error across the 3 CMJ trials was observed within both sessions for males and females, and this was most frequently observed when the CMJ height was measured by the Vertec. No systematic error was discovered across the 2 testing sessions when the maximum CMJ heights from the 2 sessions were compared. In males, the Myotest demonstrated the best intrasession reliability (intraclass correlation coefficient [ICC] = 0.95; SEM = 1.5 cm; coefficient of variation [CV] = 3.3%) and intersession reliability (ICC = 0.88; SEM = 2.4 cm; CV = 5.3%; limits of agreement = -0.08 ± 4.06 cm). Similarly, in females, the Myotest demonstrated the best intrasession reliability (ICC = 0.91; SEM = 1.4 cm; CV = 4.5%) and intersession reliability (ICC = 0.92; SEM = 1.3 cm; CV = 4.1%; limits of agreement = 0.33 ± 3.53 cm). Additional analysis revealed that heteroscedasticity was present in the CMJ when measured from all 3 devices, indicating that better jumpers demonstrate greater fluctuations in CMJ scores across testing sessions. To attain reliable CMJ height measurements, practitioners are encouraged to familiarize athletes with the CMJ technique and then allow the athletes to complete numerous repetitions until performance plateaus, particularly if the Vertec is being used.     

Real-time intersession and interrater reliability of the functional movement screen

The purpose of this study was to examine the real-time intersession and interrater reliability of the functional movement screen (FMS). The overall study consisted of 19 volunteer civilians (12 male, 7 female). The intersession reliability consisted of 12 men and 7 women, whereas 10 men and 6 women participated in the interrater reliability test session. Two raters (A and B) were involved in the interrater reliability aspect of this study. The FMS includes 7 tests: deep squat (DS), hurdle step (HS), in-line lunge (IL), shoulder mobility (SM), active straight leg raise (ASLR), trunk stability push-up (TSPU), and rotary stability (RS). Researchers analyzed the data via intraclass correlation (ICC). To determine the reliability of the intersession scoring of the FMS and the intrasession interrater scoring of the FMS a 2-way mixed effects model intraclass correlation coefficient (ICC(3,1)) was used for the continuous data, whereas a weighted Cohen's kappa (κ) was used for the categorical data. The dependent variables were FMS total score (0-21 scale) and associated tests were DS, HS, IL, SM, ASLR, TSPU, and RS. Intersession reliability (ICC, SEM) and κ were as follows: FMS total score (0.92, 0.51), DS (κ = 0.69), HS (κ = 0.16), IL (κ = 0.69), SM (κ = 0.84), ASLR (κ = 0.69), TSPU (κ = 0.77), and RS (no covariance). Interrater reliability (ICC, SEM) and κ were as follows: FMS total score (0.98, 0.25), DS (κ = 1.0), HS (κ = 0.33), IL (κ = 0.88), SM (κ = 0.90), ASLR (κ = 0.88), TSPU (κ = 0.75), and RS (no covariance). The FMS total scores displayed high intersession and interrater reliabilities. Finally, with the exception of HS, all tasks displayed moderate to high intersession reliability and good to high interrater reliability.     

Reliability assessment of ballistic jump squats and bench throws

The purpose of this investigation was to determine the test-retest reliability and coefficient of variation of 2 novel physical performance tests. Ten healthy men (22.0 +/- 3.0 years, 87.0 +/- 8.0 kg, 20.0 +/- 5.0% body fat) performed 30 continuous and dynamic jump squats (JS) and bench throws (BT) on 4 separate occasions. The movements were performed under loaded conditions utilizing 30% of subject's predetermined 1 repetition maximum in the back squat and bench press. Mean power (MP; W), peak power (PP; W), mean velocity (MV; m.s(-1)), peak velocity (PV; m.s(-1)), and total work (TW; J) were assessed using a ballistic measurement system (Innervations Inc., Muncie, IN). Data were analyzed using repeated measures analysis of variance with Duncan's post hoc test when mean differences were p < or = 0.05. Intraclass correlation coefficient (ICC) and within-subject coefficient of variation (CV%) were also calculated. All values are presented as mean +/- SE. BT variables were statistically similar across the 4 sessions: MP (350.0 +/- 13.9 W), PP (431.4 +/- 18.5 W) MV (1.6 +/- 0.03 m.s(-1)), PV (2.0 +/- 0.03 m.s(-1)), and TW (199.1 +/- 7.2 J). For JS, session 3 PP (1,669.8 +/- 111.2 W) was significantly greater vs. sessions 1, 2, and 4 (1,601.2 +/- 58.4 W). Session 4 MP (1,403.2 +/- 88.6 W) and MV (1.9 +/- 0.1 m.s(-1)) for JS were significantly lower during sessions 1, 2, and 3 (MP: 1,479.4.5 +/- 44.8 W, MV: 2.0 +/- 0.05 m.s(-1)). TW (834.7 +/- 24.3 J) and PV (2.2 +/- 0.04 m.s(-1)) were statistically similar during all sessions for JS. The CVs ranged from 3.0 to 7.6% for the BT and 3.2 to 5.7% for the JS. ICCs for MP, PP, MV, PV, and TW were 0.92, 0.95, 0.94, 0.91, and 0.95, respectively, during BT. ICCs during JS for MP, PP, MV, PV, and TW were 0.96, 0.98, 0.94, 0.94, and 0.89, respectively. The results of the current study support the use of a 30 continuous and dynamic BT protocol as a reliable upper-body physical performance test, which can be administered with minimal practice. Slightly greater variability for JS was observed, although the test had high reliability.     

The effects of polyethylene glycosylated creatine supplementation on muscular strength and power

The purpose of the present investigation was to examine the effects of 28 days of polyethylene glycosylated creatine (PEG-creatine) supplementation on 1-repetition maximum bench press (1RMBP) and leg extension (1RMLE), mean power (MP), and peak power (PP) from the Wingate Anaerobic test and body weight (BW). This study used a randomized, double-blind, placebo-controlled, parallel design. Twenty-two untrained men (mean age ± SD = 22.1 ± 2.1 years) were randomly assigned to either a Creatine (n = 10) or Placebo (n = 12) group. The Creatine group ingested PEG-creatine (5 g·d), whereas the Placebo group ingested maltodextrin powder (5 g·d). All subjects performed bench press and bilateral leg extension exercises to determine their 1RM values, and 2 consecutive Wingate Anaerobic Tests (separated by 7 minutes) on a cycle ergometer to determine MP and PP before supplementation (day 0) and after 7 (day 7) and 28 (day 28) days of supplementation. The results indicated that there was a significant (p < 0.05) increase in 1RMBP between days 0 and 28 for the Creatine group but not for the Placebo group. There were no significant changes, however, in 1RMLE, MP, PP, or BW for the Creatine or Placebo group. These findings indicated that 28 days of PEG-creatine supplementation without resistance training increased upper body strength but not lower body strength or muscular power. These findings supported the use of the PEG-creatine supplement for increasing 1RMBP strength in untrained individuals.     

Mechanically braked elliptical Wingate test: modification considerations, load optimization, and reliability

The 30-second, all-out Wingate test evaluates anaerobic performance using an upper or lower body cycle ergometer (cycle Wingate test). A recent study showed that using a modified electromagnetically braked elliptical trainer for Wingate testing (EWT) leads to greater power outcomes because of larger muscle group recruitment. The main purpose of this study was to modify an elliptical trainer using an easily understandable mechanical brake system instead of an electromagnetically braked modification. Our secondary aim was to determine a proper test load for the EWT to reveal the most efficient anaerobic test outcomes such as peak power (PP), average power (AP), minimum power (MP), power drop (PD), and fatigue index ratio (FI%) and to evaluate the retest reliability of the selected test load. Delta lactate responses (ΔLa) were also analyzed to confirm all the anaerobic performance of the athletes. Thirty healthy and well-trained male university athletes were selected to participate in the study. By analysis of variance, an 18% body mass workload yielded significantly greater test outcomes (PP = 19.5 ± 2.4 W·kg, AP = 13.7 ± 1.7 W·kg, PD = 27.9 ± 5 W·s, FI% = 58.4 ± 3.3%, and ΔLa = 15.4 ± 1.7 mM) than the other (12-24% body mass) tested loads (p < 0.05). Test and retest results for relative PP, AP, MP, PD, FI%, and ΔLa were highly correlated (r = 0.97, 0.98, 0.94, 0.91, 0.81, and 0.95, respectively). In conclusion, it was found that the mechanically braked modification of an elliptical trainer successfully estimated anaerobic power and capacity. A workload of 18% body mass was optimal for measuring maximal and reliable anaerobic power outcomes. Anaerobic testing using an EWT may be more useful to athletes and coaches than traditional cycle ergometers because a greater proportion of muscle groups are worked during exercise on an elliptical trainer.     

Test-retest reliability, criterion-related validity, and minimal detectable change of score on an abbreviated Wingate test for field sport participants

Repeat measurements in 69 young adults were performed to assess the test-retest reliability and the 95% confidence interval of the difference in score between paired observations (MDC95) of a Wingate test as abbreviated for field sport participants (test of a 15-second duration [15-secT]). Test-retest reliability was excellent for peak power output (PPO) and mean power output (MPO), independently of their mode of expression and was moderate for the fatigue index (FI). The standard errors of measurement (SEM) for absolute, relative, and derived PPO and MPO values ranged from 2.6 to 3.7%, all being smaller than the corresponding smallest worthwhile change (SWC). In contrast, FI values were rated as "marginal," with an SEM (9.6%) greater than the SWC (1.7). The range of MDC95 values for PPO and MPO were 9.9-10.4 and 7.37-7.42%, respectively. The absolute MPO showed the highest test-retest reliability and was the most effective in detecting real change. A second phase of the study evaluated the criterion-related validity of the 15-secT in 43 young men who performed 15-secT and standard 30-second Wingate anaerobic test (30-secT) in random order, on 2 separate occasions. There were no significant intertest differences in absolute, relative, or derived PPO. However, the FI for the 30-secT was greater than that for the 15-secT. Intertest correlations were highly significant for both MPOs and FIs. These findings suggest that the abbreviated Wingate test offers a reliable and valid tool for the evaluation of PPO and MPO, at least in young physical education students.     

Effect of sport practice and warm-up duration on the morning–evening difference in anaerobic exercise performance and perceptual responses to it

This study was designed to assess the effect of sport practice and warm-up duration on the morning–evening differences in muscle power and fatigue during performance of anaerobic exercise and perceptual responses to it. Twenty-two male physical education students – twelve trained (TG) (21.51 ± 1.25 years, 182.17 ± 4.37 cm and 82.88 ± 11.23 kg) and ten untrained (NTG) (23.89 ± 3.17 years, 176.8 ± 2.2 cm and 82.24 ± 8.43 kg) – participated in a crossover randomized study. They were asked to perform a 30-s Wingate test during six experimental sessions (three at 08:00 and three at 18:00 h) after different active warm-up (AWU) durations (5 min, 15 min, or 20 min). The AWU consisted of pedaling at a constant pace of 60 rpm against 50% of maximal aerobic power. Rate of perceived exertion (RPE) was recorded after the AWU and again immediately after the Wingate test. Heart rate and temperature (T) were recorded during each session at rest, after AWU and immediately at the end of the Wingate test. During the Wingate test, peak power (PP), mean power (MP), and the fatigue index were recorded. While the RPE estimations were higher in NTG, no time-of-day effect was recorded in either experimental group (morning or evening). T, PP, and MP were higher in the afternoon than in the morning (p < 0.001 for PP and MP; p < 0.05 for T). Similarly, PP and MP during the Wingate test were significantly higher in the TG than in the NTG (p < 0.001). The morning–evening difference of PP and MP was affected by AWU duration; AWU₁₅ was best in the morning for improving lower limb power for both the TG and NTG, whereas reducing this period to 5 min in the evening was appropriate for TG only.     

Local dynamic stability of treadmill walking: Intrasession and week-to-week repeatability

Repetitive falls degrade the quality of life of elderly people and of patients suffering of various neurological disorders. In order to prevent falls while walking, one should rely on relevant early indicators of impaired dynamic balance. The local dynamic stability (LDS) represents the sensitivity of gait to small perturbations: divergence exponents (maximal Lyapunov exponents) assess how fast a dynamical system diverges from neighbor points. Although numerous findings attest the validity of LDS as a fall risk index, reliability results are still sparse. The present study explores the intrasession and intersession repeatability of gait LDS using intraclass correlation coefficients (ICC) and standard error of measurement (SEM). Ninety-five healthy individuals performed 5 min treadmill walking in two sessions separated by 9 days. Trunk acceleration was measured with a 3D accelerometer. Three time scales were used to estimate LDS: over 4–10 strides (λ_4–10), over one stride (λ₁) and over one step (λ_0.5). The intrasession repeatability was assessed from three repetitions of either 35 strides or 70 strides taken within the 5 min tests. The intersession repeatability compared the two sessions, which totalized 210 strides. The intrasession ICCs (70-strides estimates/35-strides estimates) were 0.52/0.18 for λ_4–10 and 0.84/0.77 for λ₁ and λ_0.5. The intersession ICCs were around 0.60. The SEM results revealed that λ_0.5 measured in medio-lateral direction exhibited the best reliability, sufficient to detect moderate changes at individual level (20%). However, due to the low intersession repeatability, one should average several measurements taken on different days in order to better approximate the true LDS.     

Assessment of maximal cardiorespiratory performance and muscle power in the Italian Olympic judoka

The main purposes of this study were to describe the cardiorespiratory fitness and lower limbs maximal muscle power of a selected group of Olympic Italian male (M) and female (F) judokas. Eleven subjects (6 M, 5 F) underwent 3 different tests. The VO(2)max and ventilatory threshold (VT; V-slope method) were assessed during a graded maximal treadmill test. Lower limbs muscle peak power (PP) and mean power (MP) were determined during a 30-second Wingate test (WIN). Post-WIN blood lactate peak was also measured. Subjects were tested also during a 5-minute combat test (CT), during which blood lactate and heart rate (HR) were monitored. VO(2)max (mean +/- SD) was 47.3 +/- 10.9 and 52.9 +/- 4.4 ml x kg(-1) x min(-1) for M and F judokas, respectively. The VT corresponded to 80.8% (M) and 86.5% (F) of VO(2)max. Both PP and MP, measured during the WIN, were significantly higher (p < 0.05) in M than in F judokas (PP: 12.1 +/- 2.4 vs. 9.5 +/- 1.1 W x kg(-1); MP: 5.4 +/- 1.1 W x kg(-1); F: 4.3 +/- 0.5 W x kg(-1)). Post WIN blood lactate peak was 6.9 +/- 2.8 mmol x l(-1) and 6.1 +/- 1.8 mmol x l(-1) for M and F judokas, respectively (not significant). During the CT blood lactate peak was 9.9 +/- 3.0 mmol x l(-1) (M) and 9.2 +/- 2.0 mmol x l(-1) (F); these values being significantly higher than those obtained after the WIN (p < 0.05). In conclusion, Italian Olympic judokas showed high levels of muscle power but accompanied by a moderate engagement of the aerobic metabolic pathway, which is well in accordance with the characteristics of judo. Having these results in top-level athletes may represent a useful contribution to the work of coaches and trainers in optimizing training programs for the achievement of the best performance of the judoka.     

Reliability and minimal detectable change in scapulothoracic neuromuscular activity

Alterations in scapular muscle activity, including excess activation of the upper trapezius (UT) and onset latencies of the lower trapezius (LT) and serratus anterior (SA) muscles, are associated with abnormal scapular motion and shoulder impingement. Limited information exists on the reliability of neuromuscular activity to demonstrate the efficacy of interventions. The purpose of this study was to characterize the reproducibility of scapular muscle activity (mean activity, relative onset timing) over time and establish the minimal detectable change (MDC). Surface electromyography (sEMG) of the UT, LT, SA and anterior deltoid (AD) muscles in 16 adults were captured during an overhead lifting task in two sessions, one-week apart. sEMG data were also normalized to maximum isometric contraction and the relative onset and mean muscle activity during concentric and eccentric phases of the scapular muscles were calculated. Additionally, reliability of the absolute sEMG data during the lifting task and MVIC was evaluated. Both intrasession and intersession reliability of normalized and absolute mean scapular muscle activity, assessed with intraclass correlation coefficients (ICC), ranged from 0.62 to 0.99; MDC values were between 1.3% and 11.7% MVIC and 24 to 135 mV absolute sEMG. Reliability of sEMG during MVIC was ICC = 0.82–0.99, with the exception of intersession upper trapezius reliability (ICC = 0.36). Within session reliability of muscle onset times was ICC = 0.88–0.97, but between session reliability was lower with ICC = 0.43–0.73; MDC were between 39 and 237 ms. Small changes in scapular neuromuscular mean activity (>11.7% MVIC) can be interpreted as meaningful change, while change in muscle onset timing in light of specific processing parameters used in this study is more variable.     

Practice effect of the Wingate anaerobic test

The purpose of this study was to investigate the presence of a practice effect on the Wingate anaerobic test (WAnT). Twenty-five young adult men (mean age = 20 years) performed 2 trials of the WAnT, which were separated by 7 days. Mean peak power (PP) and mean power (MP) for trials I and II were compared using a 1-way repeated measures analysis of variance to determine if a practice effect existed. Mean PP and MP scores were significantly higher (p < 0.025) on trial II (867.64 and 634.68 W for PP and MP, respectively) than on trial I (764.48 and 604.92 W), indicating that a practice effect occurred. Effect size (Cohen's d) for PP and MP was 0.72 and 0.35, indicating a large effect and small effect, respectively. Therefore, at least 1 full administration should be performed prior to a baseline power output measurement.     

The effects of creatine monohydrate loading on anaerobic performance and one-repetition maximum strength

The purpose of this study was to examine the effects of 7 days of supplementation with 20 g·d?1 of creatine monohydrate (CM) on mean power (MP) and peak power (PP) from the Wingate anaerobic test (WAnT), body weight (BW), 1-repetition maximum (1RM) bilateral leg extension (LE) strength, and 1RM bench press (BP) strength. This study used a randomized, double-blind, placebo-controlled design. Twenty-two men (mean ± SD: age = 22.1 ± 2.0 years; height = 178.0 ± 5.8 cm; body weight [BW] = 77.6 ± 7.6 kg) were randomly assigned to either a supplement (SUPP; n = 10) or placebo (PLAC; n = 12) group. The SUPP group ingested 20 g·d?1 of CM powder for 7 days, whereas the PLAC ingested 20 g·d?1 of maltodextrin powder. Measurements for the PLAC and SUPP groups included BW, PP, and MP from two 30-second WAnTs (separated by 7 minutes), and 1RM strength for LE and BP. Testing was conducted before (PRE) and after (POST) 7 days of ingesting either the supplement or placebo. The results of this study indicated that there was a significant (p ≤ 0.05) increase from PRE to POST testing in MP for the SUPP group (5.4%) but not for the PLAC group (-0.3%). There were no between-group differences, however, for 1RM LE and 1RM BP strength. Furthermore, there were no changes in PP or BW for either group. The findings of this study indicated that loading with 20 g·d?1 of CM for 7 days increased MP (5.4% increase) from the WAnT, but it had no effect on strength (1RM LE and 1RM BP), PP, or BW.     

Effect of loading on enhancement of power performance over three consecutive trials

The acute effects of maximal voluntary isometric contractions (MVICs) in the squat position on subsequent measures of power output over 3 consecutive sets were investigated. Sixteen trained men experienced with back squats participated in the study. A 7-second MVIC was performed 4 minutes before the execution of 5 maximal countermovement jumps (CMJs) and was repeated for 3 consecutive sets (protocol 1). The results were compared to power output performance in a similar protocol (protocol 2) that excluded the 7-second MVICs. No significant differences occurred in any of the power output measurements between protocol 1 and protocol 2, nor did significance occur linearly across the 4 sets of CMJ, with the exception of a decrease in peak power in protocol 2 (p < or = 0.05). Using both mean and maximal values only one significant correlation between either relative strength and performance enhancement or absolute strength and performance enhancement was present at p < or = 0.01. At p < or = 0.05, significant correlations were found between absolute strength and mean peak power (PP), mean peak acceleration (PA), mean peak force (PF), max PP, max PA, max PF, and max peak velocity. These data indicate that the execution of an MVIC performed before a power exercise was inadequate to acutely enhance power output over any of 3 consecutive trials.     

Precision and Agreement of Corneal Power Measurements Obtained Using a New Corneal Topographer OphthaTOP

Purpose

To evaluate repeatability and reproducibility of anterior corneal power measurements obtained with a new corneal topographer OphthaTOP (Hummel AG, Germany) and agreement with measurements by a rotating Scheimpflug camera (Pentacam HR, Oculus, Germany) and an automated keratometer (IOLMaster, Carl Zeiss Meditec, Germany).

Methods

The right eyes of 79 healthy subjects were prospectively measured three times with all three devices. Another examiner performed three additional scans with the OphthaTOP in the same session. Within one week, the first examiner repeated the measurements using the OphthaTOP. The flat simulated keratometry (Kf), steep K (Ks), mean K (Km), J₀, and J₄₅ were noted. Repeatability and reproducibility of measurements were assessed by within-subject standard deviation (Sw), repeatability (2.77 Sw), coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Agreement between devices was assessed using 95% limits of agreement (LoA).

Results

Intraobserver repeatability and interobserver and intersession reproducibility of all measured parameters showed a 2.77 Sw of 0.29 diopter or less, a CoV of less than 0.24%, and an ICC of more than 0.906. Statistically significant differences (P<0.001) were found between the parameters analyzed by the three devices, except J₀ and J₄₅. The mean differences between OphthaTOP and the other two devices were small, and the 95% LoA was narrow for all results.

Conclusions

The OphthaTOP showed excellent intraobserver repeatability and interobserver and intersession reproducibility of corneal power measurements. Good agreements with the other two devices in these parameters were found in healthy eyes.     

Intersession reliability of a posturo-stabilometric test,using a force platform

Aim of the studyTo evaluate the intersession reliability of a posturo-stabilometric examination.MethodsSingle blind clinical trial conducted in two sessions over two weeks.44 healthy volunteers free from postural and temporomandibular disorders. All the subjects complied with the criteria for completing the study.All the subjects underwent two sessions of posturo-stabilometric examinations in different visual and mandibular conditions.Sway area, sway length and the coordinates of the center of pressure were evaluated and statistically analyzed using the Intraclass correlation coefficient (ICC).ResultsAll the posturo-stabilometric parameters seemed to have an excellent reproducibility with overall ICCs higher than 70% and good confidence intervals except for the sway area (ICC 0.422 with CI 0.283–0.560 with open eyes and ICC 0.554 with CI 0.424–0.683 with closed eyes).ConclusionsThe posturo-stabilometric examination carried out using a force platform has a good intrasession and intersession reliability, especially considering sway velocity, COP X and COP Y parameters. The force platform usefulness in analyzing static posture is confirmed in any medical field.     

Precision (Repeatability and Reproducibility) and Agreement of Corneal Power Measurements Obtained by Topcon KR-1W and iTrace

Purpose

To evaluate the repeatability and reproducibility of corneal power measurements obtained by Topcon KR-1W and iTrace, and assess the agreement with measurements obtained by Allegro Topolyzer and IOLMaster.

Methods

The right eyes of 100 normal subjects were prospectively scanned 3 times using all the 4 devices. Another observer performed additional 3 consecutive scans using the Topcon KR-1W and iTrace in the same session. About one week later, the first observer repeated the measurements using the Topcon KR-1W and iTrace. The steep keratometry (Ks), flat keratometry (Kf), mean keratometry (Km), J0 and J45 were analyzed. Repeatability and reproducibility of measurements were evaluated by the within-subject standard deviation (Sw), coefficient of variation (CoV), test-retest repeatability (2.77Sw), and intraclass correlation coefficient (ICC). Agreements between devices were assessed using Bland-Altman analysis and 95% limits of agreement (LoA).

Results

Intraobserver repeatability and interobserver and intersession reproducibility of the Ks, Kf and Km showed a CoV of no more than 0.5%, a 2.77Sw of 0.70 D or less, and an ICC of no less than 0.99. However, J0 and J45 showed poor intraobserver repeatability and interobserver and intersession reproducibility (all ICCs not greater than 0.446). Statistically significant differences existed between Topcon KR-1W and IOLMaster, Topcon KR-1W and iTrace, Topcon KR-1W and Topolyzer, iTrace and Topolyzer, iTrace and IOLMaster for Ks, Kf and Km measurements (all P < 0.05). The mean differences between Topcon KR-1W, iTrace, and the other 2 devices were small. The 95% LoA were approximately 1.0 D to 1.5 D for all measurements.

Conclusions

The Ks, Kf and Km obtained by Topcon KR-1W and iTrace showed excellent intraobserver repeatability and interobserver and intersession reproducibility in normal eyes. The agreement between Topcon KR-1W and Topolyzer, Topcon KR-1W and IOLMaster, iTrace and Topolyzer, iTrace and IOLMaster, Topcon KR-1W and iTrace were not so good, they should not be interchangeable in clinical application. Given that the intraobserver repeatability and interobserver and intersession reproducibility of corneal astigmatism measurements obtained by Topcon KR-1W and iTrace were poor, it should be cautious that Topcon KR-1W and iTrace were applied for the preparation of toric lens implantation.     

Anaerobic power of arms in teenage boys and girls: relationship to lean tissue

The purpose of this study was to describe anaerobic peak and mean power characteristics of arms as a function of age, gender and body composition among 50 girls and 50 boys 14 to 19 years of age. Peak (PP) and mean power (MP) output were determined during arm cranking (Wingate anaerobic test). Fat-free weight (FFW) was estimated from skinfolds, and lean arm volume (LAV) was determined by water displacement, corrected for fat volume. PP and MP increased progressively and significantly (P less than 0.05) with age for boys but not for the girls. Boys had significantly larger absolute PP and MP outputs than girls at comparable ages. PP and MP corrected for lean tissue volume were greater in older than younger boys (P less than 0.05), but did not vary significantly with age for girls. Absolute (W) PP and MP were highly correlated with LAV (r = 0.82; r = 0.75) and FFW (r = 0.84; r = 0.78) among boys. The respective r values for girls were 0.60 and 0.49 (LAV); 0.78 and 0.60 (FFW). Absolute peak and mean power, respectively, were more highly correlated with LAV (r = 0.90; r = 0.84) and FFW (r = 0.90; r = 0.85) for the combined data for boys and girls than for similar gender specific comparisons. In conclusion, both anaerobic PP and MP of arms during adolescence are highly correlated with lean tissue volume and fat-free weight, particularly among boys.     

Gender-related differences in maximum mechanical power output in short-term activities in children and adolescents

The study was designed to examine the gender-related differences in maximum mechanical power output in various short-burst activities during growth. The subject sample consisted of four subgroups: 9 boys (14.11 +/- 0.6 yr), 9 boys (10.67 +/- 0.71 yr), 7 girls (14.29 +/- 0.49 yr), 7 girls (10.57 +/- 0.54 yr). We measured peak power (PP), mean power (MP), fatigue index (FI) during 30-s WAnT, squat jump height (SJH) and power (SJP), and counter movement jump height (CMJH) and power (CMJP), maximum speed over 20-metre distance (S20). Lactation concentration was measured in the 3rd and 5th minutes after the WAnT Ratio normalisation and ANCOVA were used to remove the influence of the differences in muscle (MM) and body mass (BM). Male adolescents had higher absolute values of PP (P < 0.05), MP (P < 0.05) than female. Ratio normalisation showed that boys had higher PP/BM (P < 0.05), PP/MM (P < 0.05), MP/BM (P < 0.05), MP/MM (P < 0.06) than girls. The ANCOVA adjustment for MM showed differences between genders in PP (P < 0.001), MP (P < 0.001), SJH (P < 0.05), SJP (P < 0.05) and CMJP (P < 0.001), whereas the ANCOVA adjustment for BM showed differences only in PP (P < 0.001), MP (P < 0.001). Prepubertal boys had higher absolute values only in SJP (P < 0.05). We concluded that variations in body composition could not be the only key to gender-related differences in power output in short-burst activities.