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Clarke, R, Read, PJ, De Ste Croix, MBA, and Hughes, JD. The deceleration deficit: a novel field-based method to quantify deceleration during change of direction performance. J Strength Cond Res XX(X): 000-000, 2020-The study investigated the relationship between linear and change of direction (COD) speed performance components and the individual differences between deceleration deficit (DD) and COD deficit (CODD). Thirty-six subjects (mean ± SD: age = 20.3 ± 2.9 years; stature = 175.2 ± 7.7 cm; and body mass = 78.0 ± 16.7 kg) completed 3 trials of a 505 test in both turning directions (dominant [D]; nondominant [ND]) and 3 15-m linear sprints. Deceleration deficit was calculated by the 15-m approach in the 505 test, minus the athlete's linear 15-m sprint time. To compare individuals CODD and DD, z-scores were calculated, and moderate worthwhile changes (MWCs) were identified between these deficit z-scores. Significant correlations were identified between linear sprints and 505 time (D: r = 0.71, 0.74; P < 0.01. ND: r = 0.76, 0.75; P < 0.01) for 10-m and 15-m sprint. respectively, and between 505 performance and CODD (D: r = 0.74; P < 0.01. ND: r = 0.77; P < 0.01) and DD (D: r = 0.41, P < 0.05. ND: r = 0.44, P < 0.01). Deceleration deficit was significantly related to CODD (D: r = 0.59; P < 0.01. ND: r = 0.62; P < 0.01); however, 78% of subjects demonstrated differences between these deficit measures greater than an MWC. In conclusion, linear speed has the strongest significant relationship with 505 performance. Deceleration deficit could provide a more isolated construct than CODD which may be related to an athlete's deceleration capabilities.
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The Deceleration Deficit: A Novel Field-Based Method to Quantify Deceleration During
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Change of Direction Performance
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Type: Original Investigation
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Preferred Running Head: The Deceleration Deficit
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Abstract word count: 239
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Manuscript word count: 3254
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2 figure
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3 tables
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ABSTRACT
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The study investigated the relationship between linear and change of direction (COD) speed
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performance components and the individual differences between deceleration deficit (DD) and
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COD deficit (CODD). Thirty-six subjects (mean ±SD: age = 20.3 ± 2.9 years; stature = 175.2
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± 7.7 cm; body mass = 78.0 ± 16.7 kg) completed three trials of a 505 test in both turning
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directions (dominant (D); non-dominant (ND)) and three 15m linear sprints. DD was calculated
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via the 15m approach in the 505 test, minus the athlete’s linear 15m sprint time. To compare
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individuals CODD and DD, z-scores were calculated, and moderate worthwhile changes
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(MWC) were identified between these deficit z-scores. Significant correlations were identified
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between linear sprints and 505 time (D: r = 0.71, 0.74; P < 0.01. ND: r = 0.76, 0.75; P < 0.01)
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for 10m and 15m sprint respectively, and between 505 performance and CODD (D: r = 0.74;
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P < 0.01. ND: r = 0.77; P < 0.01) and DD (D: r = 0.41, P < 0.05. ND: r = 0.44, P < 0.01). DD
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was significantly related to CODD (D: r = 0.59; P < 0.01. ND: r = 0.62; P < 0.01); however,
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78% of subjects demonstrated differences between these deficit measures greater than an
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MWC. In conclusion, linear speed has the strongest significant relationship with 505
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performance. DD could provide a more isolated construct than CODD which may be related
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to an athlete’s deceleration capabilities.
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Key Words: Agility; Deceleration; Velocity; Braking; Multi-Directional
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INTRODUCTION
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Change of direction (COD) speed is a key physical quality for success in a range of sports (25).
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Assessment of COD speed often includes the 505 test (1, 9, 27, 29) or various cutting
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manoeuvres (3, 4, 18, 19), with performance quantified via the total time taken to complete a
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pre-determined course. However, COD speed is comprised of many constituent parts, including
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linear speed, deceleration and re-acceleration (25). Specifically, the 505 test involves a 15m
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approach sprint, a 180° turn, and a 5m exit; or more simply, a maximal acceleration, a
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deceleration to a complete stop (16) and a re-acceleration into the new direction. Despite the
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test already being relatively short in duration (~2.3 seconds) (1, 9), it is reported that on average
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only approximately 31% of the time is spent changing direction (23).
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Total time in a COD speed test is still a useful measure as the transfer of performance may
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primarily relate to the time taken to get from one point to another. However, an athlete may
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have varying capabilities in the different components that make up the test (acceleration,
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deceleration etc.). Providing greater insights into how the performance task is executed will
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enhance our ability to identify the main limiting factor(s); linear speed, deceleration or re-
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acceleration (22). The COD deficit (CODD) was designed to assess COD ability whilst
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controlling for linear speed, as COD abilities can be over or underestimated by total time
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measures due to an athlete’s linear speed capabilities (5, 22). The CODD is a useful tool to
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help understand if an athlete should focus on their linear speed capabilities or ability to
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decelerate, change direction and re-accelerate during the training process. However, the CODD
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is still a single variable which represents a range of qualities, such as deceleration, acceleration
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and technique factors. Therefore, delineating the primary limitations in performance remains
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challenging.
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The 505 test provides an opportunity to assess an athlete’s ability to decelerate, as momentary
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zero velocity must be attained following a 15m approach, prior to the change of direction.
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Graham-Smith et al., (11) reported that after approximately an 8.5m maximal sprint, it takes
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athletes approximately 6.5m to decelerate and come to a complete stop. Therefore, the
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approach period of the 505 test may be viewed as an 8.5m initial sprint followed by a 6.5m
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deceleration period (entry into the turn). By recording, 1) the amount of time taken to
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maximally accelerate and come to a complete stop within the 505 test (in this case 15m); and
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2) the amount of time required to cover the same distance but with no forced deceleration.
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Performance in these separate tasks could be compared and quantified as the ‘deceleration
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deficit’ (DD). This method could represent an athlete’s deceleration ability relative to their
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linear sprinting speed. Isolating this time required to come to a stop via the DD measure could
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provide important information for coaches due to the high eccentric demand experienced
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during deceleration not found in acceleration (10, 13).
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Deceleration is a key factor in COD speed performance, with the importance of braking
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impulse during the penultimate foot contact on COD performance previously reported (7, 8).
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However, our understanding of deceleration during COD speed is yet to be expanded past the
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penultimate step. The use of the DD in the 505 provides an opportunity for coaches to isolate
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the deceleration component of the task, providing unique insights into an individual’s limiting
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factor(s) when performing the test. However, there are inherent deceleration components in
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both 505 total time and the CODD. Therefore, the relationship between these measures should
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also be investigated to identify if the DD provides different and meaningful information for
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coaches.
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The aims of the current study were to; a) determine the relationship between linear sprint speed,
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505 performance, CODD and DD, and b) investigate the individual differences between DD
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and CODD. It was hypothesized that linear speed would demonstrate a strong relationship with
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505 time but not the CODD and DD. In addition, it was hypothesized that these two deficit
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measures would not be significantly correlated.
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METHODS
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Experimental Approach to the Problem
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The study utilised a cross-sectional design where subjects completed a 505 COD test in both
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turning directions and a 15m linear sprint. All experimental data for subjects was collected in
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a single testing session. Pearson’s correlation were used to determine the relationship between
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COD, linear speed and deceleration performance. Individual differences between DD and
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CODD times were compared via standardized metrics (z-scores).
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Subjects
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Thirty-six (nineteen female and seventeen male) recreationally active subjects (20.3 ± 2.9
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years; stature = 175.2 ± 7.7 cm; body mass = 78.0 ± 16.7 kg) volunteered and provided
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informed consent. Subjects were required to be competing in an invasion sport (either netball,
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hockey, rugby or football) and taking part in coached strength training at least once per week
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with experience of COD speed testing protocols. All subjects were also required to be currently
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free from injury and illness. This study was approved by the University of Gloucestershire
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institutional review board and procedures were performed in accordance with the declaration
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of Helsinki.
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Procedures
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Subjects first attended a familiarisation session to practice the 505 test and to collect
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anthropometric data. This was followed by formalized data collection 48 hours later, with three
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trials completed of the 505 in each turning direction in a randomised order, and finally three
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15m linear sprints. A two-minute rest period was provided between each recorded attempt. All
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testing was conducted on a Pulastic indoor sports floor and all subjects were instructed to wear
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clean indoor sports trainers. The testing session was preceded by a standardised warm up
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consisting of 5-min of various pulse-raising activities, including linear and multi-directional
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movements which mimicked the 505 test, and 5-min of dynamic muscle activation exercises
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such as body weight lunges and squats and dynamic stretches. Subjects were asked to refrain
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from alcohol 24 hours prior to testing and avoid caffeine ingestion the morning of testing
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procedures.
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Performance Measures
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COD Test
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The COD speed test contained the same running pattern as the 505 test commonly utilised in
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other studies (1, 9, 22). Time was recorded using a smart speed timing gate system with gates
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placed at 0 and 10m and a smart jump contact mat (Smartspeed, Fusion Sport, Sumner,
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Australia) positioned at the 15m turning point (which was temporarily fixed to the floor to
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avoid slipping). The contact mat was used to record commencement and duration of plant step
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ground contact (Figure 1). For a 505 trial to be considered successful, subjects needed to ensure
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that their final plant step occurred on the contact mat and over the marked turn line, any trials
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where subjects missed the contact or turning line were discounted and repeated. In order to
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independently analyse performance of each task component, timing splits were utilised to
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measure 0-10m, 10-15m (repeated for the returning 5m acceleration) and the GCT of the plant
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step (Table 2). Subjects began each sprint 50cm behind the first gate, in a staggered, three-
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point stance and were instructed to run as fast as possible to the contact mat, turn on the marked
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point with either their left or right leg and the return as fast as possible back through the 10m
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gate. The turning leg used for the first trial was randomly allocated and then alternated between
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trials. Any trials where the marked turning line was not met were repeated. All timing variables
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were reported to the nearest 0.01 seconds. The three trials turning left or right were averaged
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and used for analysis. The dominant direction (D) was identified as the turning direction with
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the fastest 505 performance and the opposite direction was classified as non-dominant (ND)
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(2).
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*** Insert Figure 1 here ***
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15m Linear Sprint Test
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The linear 15m sprint test was utilised in order to assess maximal acceleration capability with
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gates placed at 0, 10 and 15m. Subjects were instructed to start 50cm behind the first gate, in a
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staggered, three-point stance and sprint all the way through the 15m gate as fast as possible.
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Three trials were completed with at least a 2 minutes rest between each. Time for each distance
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and all variables were recorded to the nearest 0.01 seconds with the average of three trials being
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included for analysis.
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COD and Deceleration Deficit Calculations
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CODD was calculated to represent the individual’s ability to change direction while controlling
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for their linear speed capabilities using the equation proposed by Nimphius et al. (22). The DD
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was calculated in order to quantify the time an individual needed to come to a stop relative to
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their own sprinting speed. The full approach time was used in order to represent the time
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required to approach the turn line as fast as possible while decelerating into a position to
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facilitate exit speed and overall 505 performance. Commonly braking force is still being
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applied through the first half of plant step ground contact, with the remainder of the step used
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for the application of propulsive forces (12). A force plate would be the optimum criterion
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measure to determine the relative contribution of these braking forces but is not practically
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viable in field-based testing. Therefore, the full approach includeed the time taken over the first
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half of ground contact in an attempt to capture the complete braking phase of the approach
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(12). This time was compared against the time the athlete needs to cover the same distance in
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a linear sprint. Equations to calculate the deficit measures are shown in Table 1.
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*** Insert Table 1 here ***
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Statistical Analysis
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Statistical analysis was conducted using SPSS (PASW statistics, Version 19, IBM Corporation,
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New York, U.S.A) and Microsoft Excel (version 14.6.4, Microsoft, Redmond, DC, USA).
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Descriptive statistics (mean ± SD) were calculated for all variables. Normality was assessed
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and confirmed for all variables using a Kolmogorov–Smirnov test. Relationships between
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performance measures, were assessed using Pearson’s product-moment correlation (2-way).
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The correlations were interpreted as follows: < 0.1 trivial, 0.1-0.3 = small, 0.3 0.5 = Moderate,
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0.5 – 0.7 large, 0.7 – 0.9 = very large, 0.9-1.0 = nearly perfect, 1.0 = perfect (14). Statistical
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significance was set as p < 0.05. In addition, further analysis examined whether the DD was
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able to identify athletes whose deceleration ability limits their COD performance to a greater
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extent than CODD. These were calculated within individuals using z-scores though the
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formula:
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z-score = (subject’s test score – group mean score)/SD.
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Worthwhile differences in z-score between DD and CODD were determined and compared to
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identify those with a moderate worthwhile change (Cohens d) between the two deficit scores
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(between subject SD multiplied by 0.5). A moderate worthwhile change was used in order to
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consider the potentially lower sensitivity of the deficit measures in a population with less multi-
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direction movement expertise (28). Subsequently, subjects that had a moderate worthwhile
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positive z-score difference indicated that the use of CODD alone may result in the
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overestimation of deceleration ability and a negative moderate worthwhile difference indicated
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an underestimation of deceleration ability if CODD is used in isolation.
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RESULTS
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Descriptive statistics for all variables are reported in Table 2. Relationships between
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performance and turning directions are displayed in Tables 3 and 4 respectively. Significant
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correlations were shown between linear sprint speeds, full approach and 505 time. No
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significant relationships were reported between linear sprint speeds and CODD or DD. 505
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performance was significantly related to full approach speed, CODD and DD. Full approach
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was significantly related to CODD and DD showed a significant relationship with CODD.
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The difference in z-scores between DD and COD deficit are presented in Figure 2. 78% of
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subjects show a divergence between the two deficit measures greater than a MWC in one of
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the two turning directions (MWC = D: > 0.45. ND: > 0.44) between the CODD and DD z-
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scores on their D and ND turning directions respectively. Analysis of the effects of turning
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direction identified that 12 subjects show a MWC between deficit scores in both directions
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with the MWC consistently positive or negative, 15 subjects have a MWC in just one of the
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two turning directions and one participant has a MWC on both turning directions with the
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difference on either side changing from positive or negative.
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*** Insert Table 2, 3 and 4 here ***
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*** Insert Figure 2 here ***
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DISCUSSION
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The aims of the current study were to examine the relationships between linear sprint, 505 total
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time, CODD and DD; and investigate whether DD provides additional information to these
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previously reported variables in competitive university level athletes. The primary findings
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indicate that linear speed was related to 505 time but not CODD or DD. 505 time was
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significantly correlated to both DD and CODD and these deficit variables were significantly
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related to one another but with large individual variance.
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The results of the present study support previous research showing moderate to large
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correlations between 505 performance and linear speed (17, 22). In the current study, linear
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speed showed no significant relationship with CODD or DD. Although no previous research
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has compared DD and linear speed, relationships between these variables appear equivocal.
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Lockie et al. (17) reported a significant negative relationship between a linear 10m sprint and
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CODD (r = -0.77-82). Conversely, Nimphius et al. (22) did not find a significant relationship.
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Reasoning to elucidate these differences remain unclear and requires further investigation,
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however it may be that differences in technical proficiency were a contributing factor as the
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technical ability to apply force has been shown to be a key requirement for performance in
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linear and multi-directional tasks (7, 20). Therefore, the present results indicate that the
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athlete’s linear speed capabilities did not clearly influence either of the deficit variables.
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However, these conclusions should be considered within the performance level and technical
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proficiency of the subjects used. The subjects in this study were faster over 10m than division
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I and II womens soccer athletes (17) and were similar to experienced male cricketers (22). 505
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times were slightly slower than experienced male cricketers (22) but similar to Div II female
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soccer athletes (17). Furthermore, a moderate to large significant relationship between full
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approach and DD and large significant relationship between CODD and 505 time have been
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reported. These indicate that the inter-group performance variation was more likely due to each
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athlete’s ability to execute the COD (CODD) or deceleration (DD) components of the test.
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Therefore, DD or CODD may provide an independent measure of deceleration or COD speed
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ability respectively. These results suggest the importance of investigating both an athlete’s
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propulsive (linear sprint speed) and braking (DD or CODD) capabilities independently. This
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supports the conclusions of previous jumping tasks where concentric and eccentric impulse
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were unrelated (10, 15). This should be further investigated by assessing the DD with the
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addition of ground reaction force kinetics to explore the influence of braking and propulsive
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forces. This may be further warranted in subjects with higher levels of linear speed and
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acceleration as they may be required to decelerate from greater velocities and potentially higher
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levels of momentum (13). Caution is therefore required when applying the reported
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correlations to different populations with differing performance levels and further research is
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warranted.
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Our results suggest that while linear speed still appears to be the primary factor influencing
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505 total time, moderate significant relationships were also observed between DD and 505
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performance. Therefore, deceleration ability could also be considered an important component
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of effective COD speed performance. The importance of the penultimate foot contact braking
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impulse on COD performance has been reported previously (7, 8). However, it is likely that
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the deceleration in the 505 test was distributed over multiple steps prior to the penultimate foot
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contact as it has been reported that athletes take an average of 6.61m when accelerating and
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coming to a stop within 15m (11). The results of the present study indicate an average 0.56 ±
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0.13 seconds of additional time was required to come to a stop compared to continuing to
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accelerate over the same distance. The moderate nature of the relationship between 505 and
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DD may be due to the DD measure being relative to an individual’s linear speed capabilities.
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For example, if an athlete does not require excessive time to come to a stop, a positive factor
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for COD speed performance, they still require effective linear speed in order to complete the
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COD task quickly. Therefore, to understand the role of deceleration on COD speed in greater
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depth, future research should investigate the deceleration phase over multiple steps and DD
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should be interpreted in conjunction with linear speed.
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Only a moderate amount of shared variance was shown between the CODD and DD, which
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was likely due to deceleration time contributing to the CODD outcome (21). However, it is
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unclear from the CODD how much deceleration was contributing to the time required to
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complete the COD compared to the re-acceleration phase. The difference between CODD and
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DD z-scores shows that 78% of subjects showed a divergence between the two deficit measures
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greater than a MWC in one of the two turning directions. This suggests 78% of athletes would
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either over or underestimate their deceleration ability in one of the two turning directions if
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only the CODD was used. In 22% of the subjects, CODD provides a fair representation of their
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deceleration performance and the DD does not contribute to their performance profile in either
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turning direction.
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During COD performance assessment it is important to consider directional dominance, which
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can be accurately identified utilising the CODD (5). Addition of the DD from this study may
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provide greater insights into the contributing factors of these directional differences. A larger
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correlation was identified between DD and full approach in the ND turning direction, indicating
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that the braking phase during the full approach on the ND direction had a greater influence on
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DD outcome than on the D turning direction (D: r = 0.43; P < 0.01. ND: r = 0.54; P < 0.01).
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This may be due to the ND turning direction braking phase being slower for some athletes and
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subsequently having a greater contribution to DD. However, this was not identified from the
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group mean times and requires further investigation. Independent analysis for each turning
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direction revealed that 58% and 55% of subjects (D and ND performance respectively) had a
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divergence between the two deficit measures greater than a MWC. Further analysis identifies
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12 subjects, where the over, or under-estimation of deceleration from CODD was consistent
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on both turning directions. 15 subjects have an over, or under-estimation of deceleration from
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CODD in just one of the two turning directions. Finally, one subject had a MWC on both
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turning directions that changes from positive or negative, indicating that CODD underestimates
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deceleration ability on the D turning direction, but overestimates deceleration on the ND
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direction. CODD was reported to be a suitable representation of deceleration ability for both
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turning directions for 8 subjects. It is subsequently unclear from this analysis if there was a
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trend for the turning direction dominance to influence an over or underestimation of
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deceleration ability by CODD and further investigation is warranted.
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While the current results suggest that DD provides unique information for the majority of
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athletes which may help coaches individualise training programs, it is important that this metric
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is further investigated with validity and reliability analysis to enhance our understanding.
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Furthermore, the reported correlations between DD and the other measures variables were all
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less than r = 0.5, meaning there was only approximately a 20% contribution of these variables
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to DD. Therefore, the factors which contribute to DD are currently unknown and warrant
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exploration. The DD itself may also be contributed to by a self-paced approach speed prior to
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the deceleration phase (24) where the athlete is reducing the load exposed to their non-
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dominant limb (26) or from a lack of deceleration ability requiring the braking phase to be
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spread over a greater number of steps and more time (7, 8). At present it is not possible to
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distinguish between contributing factors such as these and future research should look to
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investigate this further utilising a multiple regression analysis and including a broad range of
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physical measures such as eccentric strength (10, 13).
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The results of the current study suggest that DD could provide a unique insight to deceleration
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capabilities which was not captured in CODD for the majority of athletes. In addition, both the
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CODD and DD were not influenced by an athlete’s linear speed capabilities supporting the
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need for independent analysis of propulsive (linear speed), braking (DD) and multi-direction
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application (CODD) qualities during COD speed testing. Further research should be conducted
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to improve our understanding of the DD and how an individual’s deceleration ability impacts
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COD speed performance, turning direction dominance, speed control and mechanics.
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PRACTICAL APPLICATIONS
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The current study indicated that the use of the DD helps identify athletes whose COD speed
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performance may be limited by deceleration ability, assisting coaches in individualising
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training interventions. The protocols used provided an opportunity to measure propulsive
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(linear speed), braking (DD) and multi-direction application (CODD) qualities during COD
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while also obtaining a general COD speed performance measure (505 time) from just two easy
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to administer field-based tests, maximising efficiency in testing.
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ACKNOWLEDGEMENTS
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We would like to acknowledge our subjects for their contribution to the study.
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22. Nimphius, S, Callaghan, SJ, Spiteri, T, Lockie, RG. Change of direction deficit: A more
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23. Nimphius, S, Geib, G, Spiteri, T, Carlisle, D. "Change of direction" deficit
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measurement in division I american football players. J Aus Strength Cond 21: 115-117,
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1839-1948, 2014.
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Figure 1: A Visual representation of the 505 COD test
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Figure 2: The difference between z-scores for COD Deficit and Deceleration Deficit with a
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moderate worthwhile change threshold.
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Table 1: A description of performance measures collected during the study
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Table 2: Descriptive statistics for linear speed and best trial COD performance measures. Mean
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± SD
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Table 3: Pearson’s correlation coefficient between performance measures in the dominant
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turning direction
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Table 4: Pearson’s correlation coefficient between performance measures in the non-dominant
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turning direction
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Figure 1: A Visual representation of the 505 COD test
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0m Gate
10m Gate
15m Contact
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50cm
Start Line
Figure 2: The difference between z-scores for COD Deficit and Deceleration Deficit with a moderate worthwhile change threshold.
-3.00
-2.50
-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
Z-score difference between DD and CODD
Participants
DOM z-score difference
Non-DOM z-score difference
CODD
underestimates
deceleration ability
CODD
overestimates
deceleration ability
Table 1: A description of performance measures collected during the study
Performance Measures
Description/Equation
Linear 10m Sprint (s)
Time from 0m to 10m when sprinting in a straight line, taken as a
split time from a 15m sprint.
Linear 15m Sprint (s)
Time from 0m to 15m when sprinting in a straight line.
505 Time (s)
Total time taken to complete the 505 test as calculated in previous
research (1).
Full Approach (s)
The time from the 0m gate to 50% of GCT of the plant step during
the 505 test.
DD (s)
Full approach during the 505 test – 15m time during linear sprint.
CODD (s)
505 time – 10m time taken during 15m linear sprint (22).
Table 2: Descriptive statistics for linear speed and best trial COD performance measures. Mean
± SD
10m Sprint
(s)
15m Sprint
(s)
505
(s)
Full
Approach (s)
CODD
(s)
DD
(s)
DOM
1.85 ± 0.14
2.59 ± 0.21
2.54 ± 0.22
3.15 ± 0.26
0.69 ± 0.16
0.56 ± 0.12
Non-DOM
2.63 ± 0.23
3.15 ± 0.28
0.78 ± 0.15
0.56 ± 0.15
Table 3: Pearson’s correlation coefficient between performance measures in the dominant
turning direction
10m
Sprint
15m
Sprint
505
Full
Approach
CODD
DD
10m Sprint
1
0.98**
0.71**
0.87**
0.06
-0.02
15m Sprint
1
0.74**
0.88**
0.12
-0.06
505
1
0.86**
0.74**
0.41*
Full Approach
1
0.40*
0.43**
CODD
1
0.59**
DD
1
* P<0.05; **P<0.01
Table 4: Pearson’s correlation coefficient between performance measures in the non-dominant
turning direction
10m
Sprint
15m
Sprint
505
Full
Approach
CODD
DD
10m Sprint
1
0.98**
0.76**
0.85**
0.16
0.05
15m Sprint
1
0.75**
0.85**
0.17
0.01
505
1
0.87**
0.77**
0.44**
Full Approach
1
0.48**
0.54**
CODD
1
0.62**
DD
1
* P<0.05; **P<0.01
... However, additional metrics such as the COD deficit (CODD) and the deceleration deficit (DD) have more recently been shown to provide meaningful and complementary information for coaches. [9][10][11] The CODD corresponds to the absolute (ie, in time or velocity) 12,13 or relative (ie, in percentage) 14 difference between a pure linear sprint and a COD test of equal distance and has been used to indicate how "efficient" an athlete is at changing direction with respect to his or her linear sprint ability (ie, the lower the CODD, the greater the efficiency). The DD consists of the difference between the time taken to accelerate and come to a complete stop when changing direction in relation to linear sprint performance. ...
... The DD consists of the difference between the time taken to accelerate and come to a complete stop when changing direction in relation to linear sprint performance. 10 This variable has been described as an isolated construct related to the ability to rapidly decelerate and can be used to identify athletes whose COD performance might be limited by their deceleration capability. 10 In light of this, and given the importance of high-intensity acceleration 8 and deceleration 15,16 efforts in multidirectional team sports, comprehensive COD assessments should include not only test completion time but also other COD-derived measurements, such as the CODD and DD. ...
... 10 This variable has been described as an isolated construct related to the ability to rapidly decelerate and can be used to identify athletes whose COD performance might be limited by their deceleration capability. 10 In light of this, and given the importance of high-intensity acceleration 8 and deceleration 15,16 efforts in multidirectional team sports, comprehensive COD assessments should include not only test completion time but also other COD-derived measurements, such as the CODD and DD. ...
Article
Full-text available
Purpose: To investigate the relationships between a series of direct and indirect measures of linear and multidirectional speed performance in elite female rugby sevens players. Methods: Nineteen players from the Brazilian national team performed 40-m linear sprint and 505 change-of-direction (COD) tests on the same day. Based on the linear sprint and COD test performances, the COD deficit (CODD) and deceleration deficit (DD) were also obtained. A Pearson product-moment correlation analysis was used to determine the relationships between linear sprint and COD-derived variables. Results: Linear sprint and 505 COD velocities were not significantly associated (P > .05). Large to very large significant associations (r values ranging from .54 to .78; P < .05) were detected between linear sprint velocity for the different distances tested (10, 15, 30, and 40 m) and CODD. The COD velocity presented a very large inverse significant correlation with CODD and DD (r = -.77 and -.79 respectively; P < .05). A large and significant correlation was identified between CODD and DD (r = .79; P < .05). Conclusions: Significant associations were observed between linear sprint and CODD, suggesting that faster players are less efficient at changing direction. No relationship was found between sprint velocity and DD, highlighting the independent nature of linear sprints and deceleration capabilities. A comprehensive and detailed analysis of multidirectional speed performance should consider not only linear sprint and COD performances but also complementary COD-derived variables such as the CODD and DD.
... Their results indicate that players producing the highest braking force have the best COD performance because it allows them to make a faster transition between the end of braking (e.g., penultimate and earlier foot contacts) and the re-acceleration (Spiteri et al., 2015). In addition, some previous research has indicated that the deceleration deficit is essential in determining the 505-test performance (Clarke et al., 2020). Although the above findings suggest that deceleration capacity is a critical factor in COD performance, our understanding of the association between deceleration capacity and COD performance is not extensive to date. ...
... It could be assumed that the 505-test and the method used to calculate mechanical parameters during linear deceleration revealed some limitations. Clarke et al. (2020) showed that approximately 78% of athletes would either over or underestimate their deceleration ability during the COD test (Clarke et al., 2020). Indeed, the 505 test does not allow athletes to reach the maximum sprint speed and, therefore, to take advantage of the maximum braking capabilities. ...
... It could be assumed that the 505-test and the method used to calculate mechanical parameters during linear deceleration revealed some limitations. Clarke et al. (2020) showed that approximately 78% of athletes would either over or underestimate their deceleration ability during the COD test (Clarke et al., 2020). Indeed, the 505 test does not allow athletes to reach the maximum sprint speed and, therefore, to take advantage of the maximum braking capabilities. ...
Article
Full-text available
The study investigated the relationship between short sprint performance and mechanical parameters obtained during the acceleration and deceleration tasks with the change of direction (COD) performance in female and male soccer players. The acceleration and deceleration ability were compared in the “High/Fast” versus “Low/Slow” COD performance group based on a median split analysis in each sex group. One hundred three French soccer players were assessed for the sprinting Force-Velocity (F-V) profile (i.e., theoretical maximal force [F0], velocity [V0], power [Pmax]), 10 m performance, linear deceleration test (maximal braking force [HBFmax], braking power [BPmax], deceleration [Decmax]), and COD performance using 505-test. The 10 m performance was strongly associated with 505-test performance (ES = [0.64 to 0.71]), whereas the sprinting F-V profiles parameters were weakly to moderately correlated with 505- performance (ES = [-0.47 to -0.38]). The BPmax was also moderately associated with 505-test performance (ES: range = [-0.55 to -0.46]). In addition, the High/Fast female COD group presented higher F0, Pmax, HBFmax, and BPmax than the Low/Slow group, whereas the male groups presented very few mechanical differences. Multiple regression analysis shows that the COD performance of male players was determined by 10 m performance and maximum deceleration power. In contrast, no statistically significant model could be found to determine the change of direction performance in female players. In conclusion, the current finding indicated that the only variable strongly associated with COD performance was the linear 10 m sprint time. In the same way, the mechanical parameters obtained from acceleration and deceleration seemed to play a non-neglectable role in this population.
... For female senior soccer players operating at the elite level, it is important to obtain valid, reliable, and precise information on COD performance (11). The use of indirect measurement approaches to obtain more detailed information on the different subphases of 505 COD performance have included the use of timing gates to obtain "deficits" in COD performance (i.e., COD and deceleration deficit) by comparing COD times to linear sprint times (28,100) and through using multiple timing gates to obtain split times in different phases of the 505 COD test (112). Although these approaches have helped to attain "proxy" indicators of the desired outcome measurement (i.e., deceleration, COD), they do not provide continuous velocity measurements to enable phase-specific COD performance profiles to be obtained. ...
... B. Young et al., 2015). From an applied perspective, we suggest that practitioners prioritise the development of deceleration and braking performance alongside acceleration and sprinting in the pursuit of improved agility performance (Clarke et al., 2022;Harper et al., 2022). Moreover, considering the faster times achieved during phase 1, yet slower times achieved during phase 2 of the Y-SprintREACT test for older and more mature players, it is probable that these players within our study were approaching the COD of the Y-SprintREACT "too fast" relative to their braking and COD ability. ...
Article
Full-text available
Training and assessment of agility is often prioritised by soccer coaches and practitioners aiming to develop multi-directional speed. Although the importance of agility is advocated throughout childhood and adolescence, limited data evidence agility performance at different stages of adolescence. The purpose of this study was to examine differences in multi-directional speed performance in youth soccer players spanning an entire soccer academy. A total of 86 male junior-elite soccer players volunteered to participate. Anthropometric data were collected, alongside performance data from a battery of physical tests including sprinting, jumping, change of direction, reaction time, and agility. Bayesian models using log-likelihoods from posterior simulations of parameter values displayed linear or curvilinear relationships between both chronological and biological age and performance in all tests other than agility and reaction time. For agility and reaction time tests, performance improved until ~14 years of age or the estimated age of peak height velocity whereby arrested development in performance was observed. Our results demonstrate that while most performance skills improve as chronological or biological age increases, measures of agility and reaction time may not. These findings support the notion that agility performance is complex and multifaceted, eliciting unique, challenging physical demands and non-linear development.
... Authors have detailed the importance of linear speed, deceleration, and reacceleration during COD manoeuvres (Ryan et al., 2022a;Sheppard & Young, 2006). Specifically with the 5-0-5 COD test beginning with acceleration, then deceleration to a complete stop and reacceleration into the new direction (Clarke et al., 2022), it would seem important to monitor these variables. The IMU insoles used in this study were found to provide a reliable way to measure acceleration, maximum speed, deceleration, and ground contact time during a modified 5-0-5 COD test. ...
Article
Full-text available
Timing gates are currently the most common piece of equipment for measuring change of direction (COD) performance, however, they provide only a total time metric. A better understanding of the kinematics and kinetics during a COD movement beyond total time would provide coaches with a more comprehensive understanding of COD movement and how it can be improved. Therefore, the aim of this study was to determine the reliability of an inertial measurement unit (IMU) insole for measuring peak acceleration, peak deceleration, maximum speed, and ground contact time during a modified 5-0-5 change of direction (COD) test. Additionally, the strength of association between these IMU variables and timing light metrics was explored. Ten elite female netball athletes (age = 24.9 ± 5.0 years, height = 180.1 ± 6.5 cm, weight = 81.3 ± 15.0 kg) performed a modified 5-0-5 COD test across three testing occasions. Analysis revealed moderate to excellent relative consistency (ICC = 0.57-0.94) and acceptable absolute consistency (CV = 1.8-9.5%). Correlations ranged from 0.04 to 0.95, with peak acceleration having the strongest correlation with total time (r = 0.95). It appears that IMU insoles can be used to reliably measure performance during a COD task and provide additional diagnostics beyond time metrics.
... In an attempt to gain additional insight into an athlete's CODS performance, researchers have recently assessed additional outcome metrics, such as COD deficit (5,10,17,23,24,34,54,82,94,104), deceleration deficit (5,7), ground contact times during the penultimate step and the plant step (14-16,21,96,102), time at different intervals of the CODS test through additional timing gates (33), and velocity in and out of the turn (15,52,101,102). Several correlational analyses have found significant relationships between these metrics and total time in the CODS test (7,10,(14)(15)(16)(17)23,52,82,94,101,102,104). These findings suggest that the addition of such outcome measures might provide useful information. ...
Article
Schneider, C, Rothschild, J, and Uthoff, A. Change-of-direction speed assessments and testing procedures in tennis: a systematic review. J Strength Cond Res 37(9): 1888-1895, 2023-Change-of-direction speed (CODS) plays an essential role in tennis match play, and CODS performance is, therefore, commonly assessed and monitored in tennis players. Thus, the aim of this systematic review was to describe test characteristics, performance metrics, test-retest reliability, construct validity, and test outcomes of tests that are used to assess CODS in tennis players. A literature search conducted on PubMed and SPORTDiscus yielded 563 results. After applying the eligibility criteria, a total of 27 studies were included in the present review. Ten unique CODS tests were identified. 505 test variations were most frequently used across all studies, and total time required to complete the test was the predominant performance metric investigated. Intrasession test-retest reliability ranged from "moderate" to "excellent." Intersession test-retest reliability as well as the effects of tennis performance, sex, and age on CODS performance were unclear given the subject demographics and the limited number of studies that investigated these aspects. In conclusion, most studies included CODS tests that exhibit longer COD entry and total distances but similar COD angles to those seen during tennis match play. All CODS tests have at least "moderate" intrasession test-retest reliability. However, to improve CODS assessment methods and to increase our current understanding of CODS performance in tennis players, there is a need to conduct more research on the intersession test-retest reliability, construct validity, and the effects of sex, age, and tennis performance and to investigate other performance metrics that might provide additional insights into CODS (e.g., phase-specific performance variables).
... In accordance with these findings being able to produce greater deceleration in the steps prior to severe COD manoeuvers, could be a deceleration strategy that not only enhances COD performance DosʼSantos et al., 2017), but also reduces lower limb joint loads and injury risk factors commonly associated with turning during the FFC of COD manoeuvers (P. A. Jones et al., 2016aJones et al., , 2016b. It is also important to note that a player's deceleration strategy could also be influenced by lower-limb strength asymmetry that manifests in a reduced ability to generate and distribute braking forces in one limb (R. Clarke et al., 2020;DosʼSantos et al., 2017;Thomas, DosʼSantos, et al., 2020). Subsequently, this would transpire in one limb providing most of the braking force application and attenuation, exposing this limb to increased mechanical loads, neuromuscular fatigue and injury risk, whilst also reducing deceleration and COD speed performances. ...
Thesis
Full-text available
Horizontal accelerations and decelerations are crucial components underpinning the many fast changes of speed and direction that are performed in team sports competitive match play. Extensive research has been conducted into the assessment of horizontal acceleration and the underpinning neuromuscular performance determinants, leading to evidence-informed guidelines on how to best develop specific components of a team sport players horizontal acceleration capabilities. Unlike horizontal acceleration, little scientific research has been conducted into how to assess horizontal deceleration, meaning the neuromuscular performance determinants underpinning horizontal deceleration are largely based on anecdotal opinion or qualitative observations. Therefore, the overall purpose of this thesis was to investigate the neuromuscular determinants of maximal horizontal deceleration ability in team sport players. Furthermore, since there are no recognised procedures on how to assess maximal horizontal deceleration ability, an important and novel aim of this thesis was to develop a test capable of obtaining reliable and sensitive data on a team sport player’s maximal horizontal deceleration ability. In part one of this thesis (chapter three) a systematic review and meta-analysis identified that high-intensity (< -2.5 m.s-2) decelerations were more frequently performed than equivalently intense accelerations (> 2.5 m.s-2) in most elite team sports competitive match play, signifying the importance of developing maximal horizontal deceleration ability in team sport players. In chapter four, a new test of maximal horizontal deceleration ability (named the acceleration-deceleration ability test – ADA test), measured using radar technology, identified a number of kinematic and kinetic variables that had good intra- and inter-day reliability and were sensitive to detecting small-to-moderate changes in maximal horizontal deceleration ability. The ADA test was used in chapters five to seven to examine associations with isokinetic eccentric and concentric knee strength capacities and countermovement and drop jump kinetic and kinematic variables, respectively. Using the neuromuscular and biomechanical determinants identified to be important for horizontal deceleration ability within this thesis, in addition to other contemporary research findings, the final part of this thesis developed an evidence-based framework that could be used by practitioners to help inform decisions on training solutions for improving horizontal deceleration ability – named the dynamic braking performance framework.
... It is also important to note that a player's deceleration strategy could also be influenced by a lower-limb strength asymmetry or avoidance strategy, which manifests in a reduced ability of one limb to contribute to the generation and distribution of braking forces [22,68,69]. Consequently, one limb would disproportionately contribute to braking, thereby exposing this limb to greater mechanical loads, neuromuscular fatigue and injury risk, whilst also reducing deceleration and COD performance. ...
Article
Full-text available
Rapid horizontal accelerations and decelerations are crucial events enabling the changes of velocity and direction integral to sports involving random intermittent multi-directional movements. However, relative to horizontal acceleration, there have been considerably fewer scientific investigations into the biomechanical and neuromuscular demands of horizontal deceleration and the qualities underpinning horizontal deceleration performance. Accordingly, the aims of this review article are to: (1) conduct an evidence-based review of the biomechanical demands of horizontal deceleration and (2) identify biomechanical and neuromuscular performance determinants of horizontal deceleration, with the aim of outlining relevant performance implications for random intermittent multi-directional sports. We highlight that horizontal decelerations have a unique ground reaction force profile, characterised by high-impact peak forces and loading rates. The highest magnitude of these forces occurs during the early stance phase (< 50 ms) and is shown to be up to 2.7 times greater than those seen during the first steps of a maximal horizontal acceleration. As such, inability for either limb to tolerate these forces may result in a diminished ability to brake, subsequently reducing deceleration capacity, and increasing vulnerability to excessive forces that could heighten injury risk and severity of muscle damage. Two factors are highlighted as especially important for enhancing horizontal deceleration ability: (1) braking force control and (2) braking force attenuation. Whilst various eccentric strength qualities have been reported to be important for achieving these purposes, the potential importance of concentric, isometric and reactive strength, in addition to an enhanced technical ability to apply braking force is also highlighted. Last, the review provides recommended research directions to enhance future understanding of horizontal deceleration ability.
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