Hanley, B

Tucker, CB

Leeds Beckett Repository

Race walking is an Olympic event dictated by a rule that states thatno visible loss of contact with the ground should occur and that theleg must be straightened from first contact with the ground until the‘vertical upright position’ (IAAF Rule 230.2). The measurement offlight times during race walking is therefore of great interest tocoaches, athletes and judges. Given the importance of flight timemeasurements, using a valid and reliable system is critical indetermining the actual duration of flight time as part of a trainingprogramme or sport science support. The aim of the study was tocompare different methodologies used to measure contact and flighttime in race walking on a treadmill.11 male world-class race walkers (1.77 m (± 0.06), 64.4 kg (± 4.7))and 7 world-class female race walkers (1.68 m (± 0.10), 56.7 kg (±11.0)) participated. The men race walked on an instrumentedtreadmill at 11, 12, 13, 14 and 15 km/h, whereas the women’s trialswere at 10, 11, 12, 13 and 14 km/h. Contact and flight times weremeasured for each trial using two in-dwelling Kistler force plates onthe treadmill that recorded vertical ground reaction forces (1000 Hz)from both feet and temporal data, a 1 m strip of an OptoJump Nextsystem (1000 Hz) placed on the treadmill and a Fastec high-speedcamera (500 Hz). Results from the OptoJump Next system wereextracted using five settings based on the number of LEDs thatneeded activating (contact begins after_contact ends when), andwere annotated as 0_0, 1_1, 2_2, 3_3 and 4_4. The force platevalues were considered the criterion values and measurements wereassessed for reliability using Intraclass Correlation Coefficients (ICC)and 95% limits of agreement (LOA: bias± random error).The OptoJump Next system provided results similar to those of the gold standard force plates, with the 0_0 setting the most reliable. Users ofthe OptoJump Next system should therefore consider this setting (which is the default setting) along with others such as minimum flight time andcontact time (typically the default is 10 ms) to achieve the most accurate results when using a treadmill. The high-speed video recordings alsoprovided very good reliability but it was occasionally difficult to subjectively identify contacts with this method. Therefore, the Optojump Nextsystem is better suited to provide more immediate results when collecting treadmill data.IntroductionMethodsResultsDiscussionThis work is supported by funds from the Carnegie School of Sport Research Development FundComparisons between Systems to Measure Contact and Flight Times during Treadmill Race WalkingCatherine B. Tucker & Brian HanleyCarnegie School of Sport, Leeds Beckett Universityc.b.tucker@leedsbeckett.ac.ukVideo 0_0 1_1 2_2 3_3 4_4ContactICC .975 .979 .965 .820 .773 .65595% CI .967 - .980 .968 - .985 .857 - .985 –.091- .967 –.153- .935 –.128 - .894LOA bias (s) –.002 –.004 .008 .021 .031 .042LOA RE (s) .022 .019 .020 .024 .029 .032FlightICC .916 .938 .879 .552 .452 .30895% CI .882 - .934 .921 - .962 .435 - .957 –.182 - .886 –.140 - .779 –.097 - .665LOA bias (s) .002 .003 –.009 –.021 –.032 –.042LOA RE (s) .020 .017 .019 .021 .025 .027

Comparisons between systems to measure contact and flight times during treadmill race walking

http://eprints.leedsbeckett.ac.uk/5177/1/ComparisonsBetweenSystemstoMeasureContactandFlightPV-TUCKER.pdf

Comparisons between systems to measure contact and flight times during treadmill race walking

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