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Carl Petersen, David Pyne, Marc Portus and Brian Dawson

Purpose:

The validity and reliability of three commercial global positioning system (GPS) units (MinimaxX, Catapult, Australia; SPI-10, SPI-Pro, GPSports, Australia) were quantified.

Methods:

Twenty trials of cricket-specific locomotion patterns and distances (walking 8800 m, jogging 2400 m, running 1200 m, striding 600 m, sprinting 20- to 40-m intervals, and run-a-three) were compared against criterion measures (400-m athletic track, electronic timing). Validity was quantified with the standard error of the estimate (SEE) and reliability estimated using typical error expressed as a coefficient of variation.

Results:

The validity (mean ± 90% confidence limits) for locomotion patterns walking to striding ranged from 0.4 ± 0.1 to 3.8 ± 1.4%, whereas for sprinting distances over 20 to 40 m including run-a-three (approx. 50 m) the SEE ranged from 2.6 ± 1.0 to 23.8 ± 8.8%. The reliability (expressed as mean [90% confidence limits]) of estimating distance traveled by walking to striding ranged from 0.3 (0.2 to 0.4) to 2.9% (2.3 to 4.0). Similarly, mean reliability of estimating different sprinting distances over 20 to 40 m ranged from 2.0 (1.6 to 2.8) to 30.0% (23.2 to 43.3).

Conclusions:

The accuracy and bias was dependent on the GPS brand employed. Commercially available GPS units have acceptable validity and reliability for estimating longer distances (600–8800 m) in walking to striding, but require further development for shorter cricket-specifc sprinting distances.

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Denise Jennings, Stuart Cormack, Aaron J. Coutts, Luke Boyd and Robert J. Aughey

Purpose:

To assess the validity and reliability of distance data measured by global positioning system (GPS) units sampling at 1 and 5 Hz during movement patterns common to team sports.

Methods:

Twenty elite Australian Football players each wearing two GPS devices (MinimaxX, Catapult, Australia) completed straight line movements (10, 20, 40 m) at various speeds (walk, jog, stride, sprint), changes of direction (COD) courses of two different frequencies (gradual and tight), and a team sport running simulation circuit. Position and speed data were collected by the GPS devices at 1 and 5 Hz. Distance validity was assessed using the standard error of the estimate (±90% confidence intervals [CI]). Reliability was estimated using typical error (TE) ± 90% CI (expressed as coefficient of variation [CV]).

Results:

Measurement accuracy decreased as speed of locomotion increased in both straight line and the COD courses. Difference between criterion and GPS measured distance ranged from 9.0% to 32.4%. A higher sampling rate improved validity regardless of distance and locomotion in the straight line, COD and simulated running circuit trials. The reliability improved as distance traveled increased but decreased as speed increased. Total distance over the simulated running circuit exhibited the lowest variation (CV 3.6%) while sprinting over 10 m demonstrated the highest (CV 77.2% at 1 Hz).

Conclusion:

Current GPS systems maybe limited for assessment of short, high speed straight line running and efforts involving change of direction. An increased sample rate improves validity and reliability of GPS devices.

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Carlo Castagna, Ferdinando Iellamo, Franco Maria Impellizzeri and Vincenzo Manzi

The aim of this study was to examine the reliability and validity of a popular field test for aerobic fitness used in soccer (45-15) in Italy. Alternating progressive 45-s runs with 15 s passive recovery until exhaustion, the test considers peak speed (PS) as a reflection of maximal aerobic speed (MAS). The validity and reliability of the 45-15 was assessed in 18 young male soccer players (age 16.7 ± 1.8 y, body mass 70 ± 7.45 kg, height 177 ± 0.5 cm, 55.62 ± 5.56 mL · kg−1 · min−1) submitted to laboratory testing for aerobic fitness and repeatedly to the 45-15. Results showed that 45-15 PS was significantly related to VO2max (r = .80, P < .001, 95%CI .47–.93) and MAS (r = .78, P = .001, 95%CI .43–.93). No significant bias between MAS 45-15 PS (P = .11) was found during the measurement-consistency study. Receiver-operating-characteristic (ROC) analysis showed that 45-15 PS was sensitive in detecting VO2max changes in subjects as revealed by area under the curve (.97; 95%CI .73–1). Players with peak 45-15 speed equal to or above 16.5 km/h (ie, ROC cutoff) may be considered to have good aerobic fitness. In light of this study’s findings, the 45-15 test may be considered a reliable and valid test to evaluate meaningful information to direct generic aerobic training in soccer.

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Patrick B. Wilson

Gastrointestinal (GI) symptoms may affect up to 90% of competitors during endurance races. Studies have typically assessed GI symptoms retrospectively or only over an acute timeframe, and information on the validity and reliability of the questionnaires employed is lacking. This investigation aimed to estimate the frequency of GI distress experienced by runners over 30 days and to establish the validity and reliability of a retrospective GI symptom questionnaire. Runners (70 men, 75 women) recorded GI symptoms with a prospective journal for 30 days. Retrospective GI symptom data were then collected after the 30-day period on two occasions within one week. GI symptoms were rated on a 0–10 scale. Descriptive statistics for GI symptoms are reported as medians (interquartile ranges) because of nonnormal distributions. Men and women experienced at least one GI symptom on 84.0% (59.8–95.1%) and 78.3% (50.0–95.2%) of runs, respectively. Moderate-to-severe GI symptoms (score of ≥5) were experienced on 13.8% (6.7–37.3%) and 21.7% (5.3–41.2%) of runs for men and women. Spearman’s rho correlations between journal ratings and retrospective questionnaire ratings ranged from 0.47 to 0.82 (all p < .001), although they were highest when journal ratings were quantified as mean 30-day values (all rho ≥ 0.59). Reliability of the retrospective questionnaire ratings was high (rho = 0.78–0.92; p < .001). In comparison with tracking GI symptoms with a daily journal, retrospective questionnaires seem to offer a convenient and reasonably valid and reliable method of quantifying GI symptoms over 30 days.

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Martin Buchheit, Matt Spencer and Said Ahmaidi

Purpose:

Two studies involving 122 handball players were conducted to assess the reliability, usefulness, and validity of a repeated shuttle-sprint and jump ability (RSSJA) test. The test consisted of 6 × (2 × 12.5-m) sprints departing on 25 s, with a countermovement jump performed during recovery between sprints.

Methods:

For the reliability and usefulness study, 14 well-trained male handball players performed the RSSJA test 7 d apart. Reliability of the test variables was assessed by the typical error of measurement, expressed as a coefficient of variation (CV). The minimal changes likely to be “real” in sprint time and jump power were also calculated. For the validity study, players of seven teams (national to international levels, women and men) performed the RSSJA test.

Results:

CV values for best and mean sprint time were 1.0% (90% CL, 0.7 to 1.6) and 1.0% (90% CL, 0.7 to 1.4). CV values for best and mean jump peak power were 1.7% (90% CL, 1.2 to 2.7) and 1.5% (90% CL, 1.1 to 2.5). The percent sprint and jump decrements were less reliable, with CVs of 22.3% (90% CL, 15.7 to 38.3) and 34.8% (90% CL, 24.2 to 61.8). Minimal changes likely to be “real” for mean sprint time and jumping peak power were -2.6% and 4.8%. Qualitative analysis revealed that the majority of between-team differences were rated as “almost certain” (ie, 100% probability that the true differences were meaningful) for mean sprint and jump performances.

Conclusion:

The RSSJA test is reliable and valid to assess repeated explosive effort sequences in team sports such as handball. Test results are likely to be representative of gender and competition level; thus the test could be used to discriminate across playing standards and monitor fitness levels.

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James P. Veale, Alan J. Pearce and John S. Carlson

Purpose:

The aim of this study was to test the reliability and construct validity of a reactive agility test (RAT), designed for Australian Football (AF).

Methods:

Study I tested the reliability of the RAT, with 20 elite junior AF players (17.44 ± 0.55 y) completing the test on two occasions separated by 1 wk. Study II tested its construct validity by comparing the performance of 60 participants (16.60 ± 0.50 y) spread over three aged-matched population groups: 20 athletes participating in a State Under-18 AF league who had represented their state at national competitions (elite), 20 athletes participating in the same league who had not represented their state (subelite), and 20 healthy males who did not play AF (controls).

Results:

Test-retest reliability reported a strong correlation (0.91), with no significant difference (P = .22) between the mean results (1.74 ± 0.07 s and 1.76 ± 0.07 s) obtained (split 2+3). Nonparametric tests (Kruskal-Wallis and Mann-Whitney) revealed both AF groups performed significantly faster on all measures than the control group (ranging from P = .001 to .005), with significant differences also reported between the two AF groups (ranging from P = .001 to .046). Stepwise discriminant analyses found total time discriminated between the groups, correctly classifying 75% of the participants.

Conclusions:

The RAT used within this study demonstrates evidence of reliability and construct validity. It further suggests the ability of a reactive component within agility test designs to discriminate among athletes of different competition levels, highlighting its importance within training activities.

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Pedro Jiménez-Reyes, Pierre Samozino, Fernando Pareja-Blanco, Filipe Conceição, Víctor Cuadrado-Peñafiel, Juan José González-Badillo and Jean-Benoît Morin

Purpose:

To analyze the reliability and validity of a simple computation method to evaluate force (F), velocity (v), and power (P) output during a countermovement jump (CMJ) suitable for use in field conditions and to verify the validity of this computation method to compute the CMJ force–velocity (Fv) profile (including unloaded and loaded jumps) in trained athletes.

Methods:

Sixteen high-level male sprinters and jumpers performed maximal CMJs under 6 different load conditions (0–87 kg). A force plate sampling at 1000 Hz was used to record vertical ground-reaction force and derive vertical-displacement data during CMJ trials. For each condition, mean F, v, and P of the push-off phase were determined from both force-plate data (reference method) and simple computation measures based on body mass, jump height (from flight time), and push-off distance and used to establish the linear Fv relationship for each individual.

Results:

Mean absolute bias values were 0.9% (± 1.6%), 4.7% (± 6.2%), 3.7% (± 4.8%), and 5% (± 6.8%) for F, v, P, and slope of the Fv relationship (SFv), respectively. Both methods showed high correlations for Fv-profile-related variables (r = .985–.991). Finally, all variables computed from the simple method showed high reliability, with ICC >.980 and CV <1.0%.

Conclusions:

These results suggest that the simple method presented here is valid and reliable for computing CMJ force, velocity, power, and Fv profiles in athletes and could be used in practice under field conditions when body mass, push-off distance, and jump height are known.

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Jose A. Rodríguez-Marroyo and Carlos Antoñan

Purpose:

The purpose of this study was to examine the concurrent and construct validity of the Borg (0–10) and children’s OMNI scales for quantifying the exercise intensity and training load (TL) in youth soccer players.

Methods:

Twelve children (mean ± SD age 11.4 ± 0.5 y, height 154.3 ± 6.5 cm, body mass 39.5 ± 5.4 kg) took part in this study. Exercise intensity and TL were calculated on the basis of the session rating of perceived exertion (sRPE) and heart rate (HR; Edwards method) during 20 technical-tactical training sessions. Players’ sRPEs were obtained from the Borg and OMNI scales.

Results:

Low correlations between HR-based TL and sRPE TL based on the Borg (r = .17, P = .335) and OMNI (r = .34, P = .007) scales were obtained. Significant (P < .001) relationships in sRPE (r = .76) and TL (r = .79) between RPE scales were found.

Conclusion:

The current data do not support the relationship between the sRPE and HR methods for quantifying TL in youth soccer players. However, the sRPE method could be considered a better indicator of global internal TL, since sRPE is a measure of both physical and psychological stress. In addition, the authors demonstrated the construct validity for the OMNI scale to control exercise demands.

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Jace A. Delaney, Heidi R. Thornton, Tannath J. Scott, David A. Ballard, Grant M. Duthie, Lisa G. Wood and Ben J. Dascombe

High levels of lean mass are important in collision-based sports for the development of strength and power, which may also assist during contact situations. While skinfold-based measures have been shown to be appropriate for cross-sectional assessments of body composition, their utility in tracking changes in lean mass is less clear.

Purpose:

To determine the most effective method of quantifying changes in lean mass in rugby league athletes.

Methods:

Body composition of 21 professional rugby league players was assessed on 2 or 3 occasions separated by ≥6 wk, including bioelectrical impedance analysis (BIA), leanmass index (LMI), and a skinfold-based prediction equation (SkF). Dual-X-ray absorptiometry provided a criterion measure of fat-free mass (FFM). Correlation coefficients (r) and standard errors of the estimate (SEE) were used as measures of validity for the estimates.

Results:

All 3 practical estimates exhibited strong validity for cross-sectional assessments of FFM (r > .9, P < .001). The correlation between change scores was stronger for the LMI (r = .69, SEE 1.3 kg) and the SkF method (r = .66, SEE = 1.4 kg) than for BIA (r = .50, SEE = 1.6 kg).

Conclusions:

The LMI is probably as accurate in predicting changes in FFM as SkF and very likely to be more appropriate than BIA. The LMI offers an adequate, practical alternative for assessing in FFM among rugby league athletes.

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Michael Wilkinson, Damon Leedale-Brown and Edward M. Winter

Purpose:

We examined the validity and reproducibility of a squash-specifc test designed to assess change-of-direction speed.

Methods:

10 male squash and 10 male association-football and rugby-union players completed the Illinois agility run (IAR) and a squash change-of-direction-speed test (SCODS) on separate days. Tests were repeated after 24 h to assess reproducibility. The best time from three attempts was recorded in each trial.

Results:

Performance times on the IAR (TE 0.27 s, 1.8%, 90% CI 0.21 to 0.37 s; LOA -0.12 s ± 0.74; LPR slope 1, intercept -2.8) and SCODS (TE 0.18 s, 1.5%, 90% CI 0.14 to 0.24 s; LOA 0.05 s ± 0.49; LPR slope 0.95, intercept 0.5) were reproducible. There were no statistically significant differences in performance time between squash (14.75 ± 0.66 s) and nonsquash players (14.79 ± 0.41 s) on the IAR. Squash players (10.90 ± 0.44 s) outperformed nonsquash players (12.20 ± 0.34 s) on the SCODS (P < .01). Squash player rank significantly correlated with SCODS performance time (Spearman’s ρ = 0.77, P < .01), but not IAR performance time (Spearman’s ρ = 0.43, P = .21).

Conclusions:

The results suggest that the SCODS test is a better measure of sport-specific capability than an equivalent nonspecific field test and that it is a valid and reliable tool for talent identification and athlete tracking.