DATA ANALYSIS

Through the course of the sprint, instantaneous torque was recorded directly and instantaneous power calculated as instantaneous torque x cadence. The completion of 20 half crank cycles (10 half cycles by each leg) was established as a point of reference for comparative analysis. Analysis of instantaneous data was conducted as per the original inertial-load test methodology described by

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Martin et al. (1997). For each half crank cycle instantaneous peak torque (Ti) and power (Pi),

representing the highest values of torque and power during contractions of each leg and values of torque and power averaged over a full revolution alternating right to left and left to right legs (Trev ,

Prev), were derived from the raw data. Since the initial pedal stroke started part way through the first

half crank cycle, data pertaining to Trev1 and Prev1 was incomplete and hence these points were

omitted. The crank angle where peak torque was produced (PTA) was then, additionally, determined for each half crank cycle. The highest values of the instantaneous and averaged measures were established as Ti_max, Trev_max, Pi_max and Prev_max ; the half crank cycle where peak power values were

produced recorded as HCC Pi_max and HCC Prev_max. The instantaneous data was then used to derive

the torque- and power- cadence relationships for both peak and averaged values using linear and quadratic regressions, respectively. The quadratic regression applied a 2nd order polynomial constrained to pass through the origin.

Intercepts of the torque-cadence linear relationship, representing maximal instantaneous and average torque, Ti0 and Trev0, and cadence, fi0 and frev0 , were then obtained by extrapolation. Apex of

the instantaneous and average power-cadence quadratic relationships, Pqi_max and Pqrev_max , and

corresponding cadence value, representing optimal cadence, fqi_opt and fqrev_opt, were calculated as

the vertex of the quadratic equation. Data points from each half crank cycle and those derived from the regression equations, were compared across the 3 trial conditions at each of the 4 testing points. A summary of instantaneous measures is presented in Table 3.3.

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Table 3.3 Summary of Instantaneous Measures Analysed.

MEASURE DESCRIPTION

Ti 1-20 Peak torque of half crank cycles 1-20

Trev 2-20 Torque per revolution alternating right/left half crank cycles 2-20

Ti_max Maximum value of Ti produced

Trev_max Maximum value of Trev produced

PTA 1-20 Crank angle where Ti was produced (half crank cycles 1-20)

Ti0 Extrapolated torque intercept value of linear Ti - cadence relationship

fi0 Extrapolated cadence intercept value of linear Ti - cadence relationship

Trev0 Extrapolated torque intercept value of linear Trev - cadence relationship

frev0 Extrapolated cadence intercept value of linear Trev - cadence relationship

Pi 1-20 Peak power of half crank cycles 1-20

Prev 2-20 Power per revolution alternating right/left half crank cycles 2-20

Pi_max Maximum value of Pi produced

Prev_max Maximum value of Prev produced

HCC Pi_max Half crank cycle where Pi_max was produced

HCC Prev_max Half crank cycle where Pi_max was produced

Pqi_max Apex of quadratic Pi - cadence relationship

Pqrev_max Apex of quadratic Prev - cadence relationship

fqi_opt Optimal cadence derived from quadratic Pi - cadence relationship

fqrev_opt Optimal cadence derived from quadratic Prev - cadence relationship

To assess the effects of the potentiation protocols on distinct phases of the sprint, performance was then divided into the segments presented in Table 3.4. Markers creating start and end points for the segment data were established by calculating the equivalent metres of development for one crank cycle and multiplying by the number of crank cycles representing the beginning and duration of the segment. Data was then analysed over an equivalent distance of the sprint.

A number of performance variables were derived from the raw data and compared within each segment or as an overall outcome, as indicated in Table 3.5. Average values represented the measure averaged across the cranks cycles with the segment. Peak overall values were the highest value achieved across the whole effort. Time to peak value was the time from start of the sprint to the highest value. Final value was the value at the end of the sprint. Rate of power development was

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calculated as power at the end of the segment minus power at the start of the segment divided by time taken for the segment. Work done was calculated as the area under the power-time curve. Change in peak torque angle (PTA) was derived from the absolute angles at which peak instantaneous torque was produced for each half crank cycle: this angle is seen to move to progressively later in the crank cycle with increasing cadence. Change in PTA is then calculated as the angle for the final half crank cycle minus that of the first half crank cycle within the segment.

Table 3.4 Sprint Segments of Analysis.

SEGMENT DESCRIPTION

S1 Half crank cycles 1-2

S2 Half crank cycles 3-4

S3 Half crank cycles 5-10

S4 Half rank cycles 11-20

S1-4 Half crank cycles 1-20

Table 3.5 Summary of Segment and Overall Measures Analysed.

VARIABLE SEGMENT MEASURES OVERALL MEASURES

POWER average, rate of power development peak, time to peak

TORQUE average, change in peak torque angle peak, time to peak

CADENCE average final

VELOCITY average final

WORK DONE total

PERFORMANCE TIME total