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. 2024 Mar 8;19(3):e0299592. doi: 10.1371/journal.pone.0299592

Evaluation of variability in performance and paw placement patterns by dogs completing the dog walk obstacle in an agility competition

Juli K DiMichele 1, Arielle Pechette Markley 1, Abigail Shoben 2, Nina R Kieves 1,*
Editor: Cord M Brundage3
PMCID: PMC10923472  PMID: 38457394

Abstract

The objective of this study was to describe paw placement patterns for canine athletes completing the dog walk obstacle during canine agility trials. It was hypothesized that dogs would demonstrate defined sets of paw placement patterns as they complete the dog walk obstacle and that those could be classified based on end contact behavior. Videos of 296 dogs attempting the dog walk obstacle at the 2021 UK Agility International (UKI) US Open were reviewed online. Data observed from video evaluation included front and rear limb paw placement across the dog walk and time to complete the obstacle. Results showed a high variability in obstacle performance. Mean time to complete the entire obstacle was 2.26 seconds (sd = 1.03). Mean and median completion times were qualitatively similar across all height classes. A slight majority of dogs hit the up ramp with their right foot first indicating running on their left lead (n = 185, 63%) with some variation observed between heights. Likewise, a slight majority (58%) of dogs hit the down ramp with their right front foot first (151/262). Given the high variation in completion times and paw placements, we could not identify clear patterns of dog walk performance. The large amount of variation observed with the dog walk obstacle suggests a need for future studies to employ alternative methods for objective gait analysis and to strategically select dogs to reflect the large variety in obstacle performance observed here.

Introduction

Canine agility performance has exponentially grown in popularity over the last 10 years, and with it the need for objective information regarding performance kinematics as well as associated agility-related injuries. During canine agility trials, a handler directs a canine athlete through a set of obstacles while being timed. The goal of an agility trial is to perform all obstacles without making a mistake, or fault, in the least amount of time possible. Obstacles commonly observed in canine agility trials include the dog walk, seesaw, A-frames, tunnels, weave poles and bar jumps [1, 2]. Canine athletes performing agility are at risk for injuries due to the chronic repetitive nature of agility training, as well as risk of acute injuries while performing at high speeds [1]. The most common injuries previously reported include the shoulder, iliopsoas muscle, neck and spine including the lumbosacral junction and sacroiliac joint [36]. The rate of injury reported in agility dogs is up to 42% [36], with 33% of dogs who undergo significant musculoskeletal injuries being unable to return to competition or returning to competition at lower heights [7].

Of the obstacles evaluated in canine agility trials, there has been minimal research regarding the dog walk obstacle, which is reportedly one of the more common obstacles associated with a higher risk of injury [4]. The dog walk obstacle requires the canine competitor to ascend one ramp, cross a flat center section and then descend another ramp to complete the obstacle. The top center section is flat and is consistently 48 inches above the ground. The three planks are 12 feet long and 12 inches wide and must be connected to minimize the risk of a dog’s foot getting caught. The surfaces of the planks must be non-slip and slats are placed across the ramp sections to provide appropriate footing. Dogs must touch a contact zone with any part of one foot prior to exiting the obstacle otherwise they will receive a fault. The contact zone is confined to the lower portion of the down ramp and is distinguished from other parts of the ramp using a color specification, so it is easily identifiable by spectators and judges [2]. The exact length of the contact zone varies slightly between organizations (between 36 and 42 inches).

The requirement to touch the contact zone encourages handlers to train a specific end contact behavior. One common approach is a “2 on 2 off” contact behavior, where the dog is trained to fully stop at the end of the dog walk with their front paws on the ground and both rear feet in the contact zone on the down ramp. Another approach is to train a “running” contact behavior where the dog is trained to adjust their striding down across the dog walk to consistently have paws hit in the contact zone on the down ramp. Other approaches are reported less frequently [8], including a stop at the end of the down ramp with all 4 feet still on the obstacle and so-called “managed” contacts where the handler encourages the dog to slow down in order to have a paw touch the contact zone before continuing. While performing the obstacle, the dog is quickly alternating between uphill to downhill movements, which dictates them to change their pace and recruit different muscle groups in a matter of seconds. They must also quickly change from propulsive forces while ascending the up ramp to braking forces while descending on the down ramp.

Agility sports lack current data regarding definition of canine running styles, effective patterns for all obstacles and the long-term consequences for injury risk and the longevity of the canine athlete. A previous study [9] was able to clearly define paw placement pattern styles during completion of the weave pole obstacle, with five distinctive gait styles being identified.

To date, no evaluation of how dogs complete the dog walk obstacle has been performed. If distinctive running patterns are seen, as with the weave pole study, it could help plan for prospective analysis of dogs completing this obstacle and potentially determine risk factors for injury [9]. It would also help inform methodology of kinematic research studies regarding canine agility. Therefore, the objective of this study was to describe paw placement patterns for canine athletes completing the dog walk obstacle during canine agility trials. We hypothesized that dogs would demonstrate a number of identifiable paw placement patterns as they complete the dog walk obstacle.

Materials and methods

All runs of the Last Chance Masters Agility course from the 2021 UK Agility International (UKI) U.S. Open were watched on a web video viewer (Youtube) in slow motion speed (0.25x). All videos were watched by a single primary reviewer (JKD). Reviewer consistency was separately estimated by having two additional reviewers assess approximately 10% of runs. All data presented reflect the original observations of the primary reviewer to maximize the internal validity of the study. The videos of the competition were provided by 4LeggedFlix (https://4leggedflix.com/). The dog walk obstacle was the sixteenth obstacle to be performed and was completed after a curved tunnel obstacle. The dog would complete the curved tunnel and then head straight to the dog walk up ramp. The obstacle following the dog walk was a bar jump. The camera position was fixed on the right side of the dog and followed the dog for the length of the dog walk (Fig 1). The courses remained the same for each run and the camera angle was similar across all height categories; however, occasionally the human-operated camera would not move in time to observe the dog as it initially contacted the down ramp. As the video recordings reviewed were made by 4LeggedFlix for their coverage of the event, additional camera views were not available.

Fig 1. Agility course layout.

Fig 1

Illustration of the agility course in the exact layout that was performed and observed by the current study. Image obtained directly from UKI International website: https://ukagilityinternational.com/wp-content/uploads/2021/11/Friday-print.pdf.

Specific data to be obtained regarding each agility run was pre-determined by the authors after an initial brief review of the video footage. Information obtained from the video about the time of the first contact with the dog walk, time to complete each section, and paw placement in each section was recorded using a Qualtrics survey. Times recorded were used by the timer provided by 4LeggedFlix in the YouTube video or with a handheld stopwatch (Apple, iPhone X). Completion time was defined by the time when the dog’s first paw contacted the up ramp to the time when all four paws were no longer in contact with the obstacle. Time for the up ramp was recorded from time of initial contact to time of first contact with the middle ramp. Time for the middle ramp was recorded from time of first paw contact to time of first paw contact with the down ramp or time at which half the dog’s body was over the down ramp. Time for the down ramp was from first paw contact (or half the dog’s body over the down ramp) to the time when all four paws no longer in contact with the obstacle. For each ramp (up, middle, and down), the number of front paw hits (both front paws contacting the ramp) and rear paw hits was also recorded. Similarly, the first paw to contact each ramp was also recorded, as was the first paw to contact the ground after completing the obstacle. For the contact zone at the end of the down ramp, the number of paws that appeared to touch the contact zone was recorded. On the down ramp, the reviewer’s judgement about if the dog appeared to slow down (or stop) was recorded, as was if the dog appeared to jump off the obstacle. If the dog appeared to stop, the location of the stop(s) were recorded, including if the dog fully stopped in the “2 on 2 off” position with its front feet on the ground and rear feet touching the obstacle. Additional observations recorded included which side of the ramp the handler was on during the obstacle completion, and if the dog completed the obstacle at the correct point of the course.

Breed and other signalment information was not available. UKI jump height category for all dogs was available from the online information for the event. Jump height categories are based on measured height at the withers, so dogs were divided into four height classes based on UKI jump height class gathered from the online data available. The four categories were <12.75”, 12.75–17.5”, >17.5–22”, and >22”.

Descriptive statistics (mean and median for time variables and percentages for categorical ones) by height category were used to assess overall performance and explore differences by height of the dog. Exploratory statistical tests for differences by height were performed to provide additional context for the descriptive statistics, with no adjustments made for multiple comparisons. These tests were done using a multivariate Wald test following linear regression with robust standard errors for mean completion time and using chi square tests for categorical paw strike variables.

Reviewer consistency was estimated as percent agreement and Krippendorf’s alpha for categorical variables and the concordance correlation coefficient (CCC) for the continuous time variables. All analyses were performed using Stata version 15.1 (StataCorp, College Station, TX).

Results

A total of 296 dog walk attempts (at least one paw on the obstacle) were observed among all videoed runs of this course. Nearly all dogs (n = 283, 96%) took the obstacle in the flow of the course (after completing a u-shaped tunnel). Of the remaining 13 dogs, 11 attempted the dog walk after being resent to the u-shaped tunnel following a reset and 2 attempted the obstacle after a reset and without first completing the u-shaped tunnel. Similarly, nearly all dogs (n = 281, 95%) attempted the dog walk with the handler to the left side of the obstacle with the remaining dogs (n = 15) attempting the obstacle with the handler on the right side. Mean time to complete the entire obstacle was 2.26 seconds (sd = 1.03), with mean and median times similar across height classes (p = 0.70, Table 1). Height categories reflected the distribution of dogs competing at this event, with the most dogs in the >17.5–22” category (n = 129, 44%), followed by >22” (n = 81, 27%), 12.75–17.5” (n = 63, 21%), and <12.75” (n = 23, 8%).

Table 1. Dog walk performance times by height category.

Height at the withers
All dogs (n = 296) <12.75” (n = 23) 12.75–17.5” (n = 63) >17.5–22” (n = 129) >22” (n = 81) P for difference
Up Ramp Mean (SD) 0.63 (0.25) 0.79 (0.31) 0.67 (0.20) 0.60 (0.28) 0.59 (0.17) 0.003
Median (25th, 75th) 0.6 (0.5, 0.7) 0.7 (0.6, 0.8) 0.6 (0.5, 0.8) 0.5 (0.5, 0.7) 0.6 (0.5, 0.6)
Middle Ramp Mean (SD) 0.76 (0.35) 1.02 (0.52) 0.82 (0.39) 0.73 (0.31) 0.68 (0.26) 0.006
Median (25th, 75th) 0.7 (0.6, 0.8) 0.8 (0.7, 1.4) 0.7 (0.6, 0.9) 0.7 (0.6, 0.9) 0.7 (0.5, 0.8)
Down Ramp Mean (SD) 0.88 (0.72) 0.71 (0.36) 0.78 (0.73) 0.92 (0.68) 0.93 (0.83) 0.098
Median (25th, 75th) 0.6 (0.4, 1.2) 0.6 (0.4, 1.0) 0.5 (0.4, 0.9) 0.7 (0.4, 1.3) 0.5 (0.4, 1.2)
Entire Obstacle Mean (SD) 2.26 (1.03) 2.51 (1.12) 2.27 (0.98) 2.25 (1.01) 2.21 (1.07) 0.70
Median (25th, 75th) 2.0 (1.5, 2.7) 2.0 (1.7, 3.2) 2.0 (1.6, 2.7) 2.1 (1.5, 2.7) 1.8 (1.5, 2.6)

A slight majority of dogs hit the up ramp with their right foot first indicating running on their left lead (n = 185, 63%) with taller dogs more likely to strike with their right foot first than shorter dogs (p = 0.001, Table 2). Likewise, a slight majority of dogs hit the down ramp with their right front foot first (n = 151; 58% among the 262 dogs observed). There was a difference by height of the dog (p = 0.002), with shorter dogs slightly more likely to hit with their left foot first. As expected, the total number of hits with the front and rear feet was lower for the taller dogs, particularly for the up and middle ramps. A majority of taller dogs completed the up and middle ramps with exactly two front and rear foot hits and a larger percentage of shorter dogs needed three (or more) hits to complete these two ramps (Table 2).

Table 2. Dog walk paw strikes by height category.

Height at the withers
All dogs (n = 296*) <12.75 (n = 23) 12.75–17.5 (n = 63) >17.5–22 (n = 129) >22 (n = 81) P for difference
First Paw to hit
Up ramp 0.001
Right 185 (63%) 12 (52%) 27 (44%) 95 (74%) 51 (63%)
Left 110 (37%) 11 (48%) 35 (56%) 34 (26%) 30 (37%)
Not observed 1 (0.3%) 0 (0%) 1 (2%) 0 (0%) 0 (0%)
Down ramp 0.002
Right 151 (51%) 8 (35%) 21 (33%) 81 (63%) 41 (51%)
Left 111 (38%) 9 (39%) 33 (53%) 37 (29%) 32 (40%)
Not observed 33 (11%) 6 (26%) 9 (14%) 10 (8%) 8 (10%)
Front foot hits (1 hit = both paws)
Up ramp <0.001
<2 31 (10%) 0 (0%) 1 (2%) 18 (14%) 12 (15%)
2 194 (66%) 5 (22%) 40 (63%) 89 (69%) 60 (74%)
3 57 (19%) 11 (48%) 16 (25%) 22 (17%) 8 (10%)
>3 14 (5%) 7 (30%) 6 (10%) 0 (0%) 1 (1%)
Middle ramp <0.001
<2 47 (16%) 0 (0%) 6 (10%) 21 (16%) 20 (25%)
2 128 (43%) 10 (43%) 27 (43%) 58 (45%) 33 (41%)
3 100 (34%) 5 (22%) 20 (32%) 48 (37%) 27 (33%)
>3 21 (7%) 8 (35%) 10 (16%) 2 (2%) 1 (1%)
Down ramp 0.001
<2 67 (23%) 0 (0%) 9 (14%) 35 (27%) 23 (29%)
2 91 (31%) 9 (39%) 31 (49%) 30 (23%) 21 (26%)
3 58 (20%) 8 (35%) 13 (21%) 22 (17%) 15 (19%)
>3 79 (27%) 6 (26%) 10 (16%) 42 (33%) 21 (26%)

*one dog fell off the dog walk prior to the down ramp so n = 295 for down ramp variables.

A variety of behaviors were observed around the contact zone on the down ramp. From video it appeared that 21% (n = 61) of dogs missed the contact zone completely with nearly all (93%, n = 57) of these dogs appearing to jump off the obstacle prior to the contact zone (1 dog fell and the other 3 were large dogs who appeared to run over the down ramp without touching the contact zone). Only 38 dogs (13%) fully stopped in the classic “2 on 2 off” position and this varied by height category, with the larger dogs more likely to stop in this position (Table 3, p = 0.066 for any difference in contact behavior by height). A true “running contact” type performance where the dog hit the contact and appeared to move through the contact zone at a consistent speed was observed for 77 dogs (26%), while the remaining 119 (40%) dogs touched the contact, but subsequently jumped off the obstacle. Most dogs appeared to run over the dog walk at a consistent speed (62%, n = 180, Table 4) and the remaining dogs either stopped completely (18%, n = 52) or slowed down at least somewhat (20%, n = 59), with shorter dogs more likely to maintain a consistent speed (p = 0.010).

Table 3. Observed contact behavior (p for difference = 0.066).

Height at the withers
All dogs (n = 295) <12.75 (n = 23) 12.75–17.5 (n = 63) >17.5–22 (n = 129) >22 (n = 81)
Missed contact 61 (20.7%) 3 (13.0%) 20 (31.8%) 22 (17.1%) 16 (20.0%)
“2 on 2 off” stop 38 (12.9%) 0 (0.0%) 4 (6.4%) 19 (14.7%) 15 (18.8%)
Running 77 (26.1%) 8 (34.8%) 13 (20.6%) 38 (29.5%) 18 (22.5%)
Other* 119 (40.3%) 12 (52.2%) 26 (41.3%) 50 (38.8%) 31 (38.8%)

*Other behavior was touching the contact zone with at least one paw and subsequently jumping off the obstacle.

Table 4. Observed deceleration on the down ramp (p for difference = 0.010).

Height at the withers
All dogs (n = 295) <12.75 (n = 23) 12.75–17.5 (n = 63) >17.5–22 (n = 129) >22 (n = 81)
Full stop 52 (17.9%) 0 (0.0%) 7 (11.3%) 28 (22.1%) 17 (21.5%)
Slowing down 59 (20.3%) 3 (13.0%) 8 (12.9%) 31 (24.4%) 17 (21.5%)
No change 180 (61.9%) 20 (87.0%) 47 (75.8%) 68 (53.5%) 45 (57.0%)

Performance on the down ramp varied more between dogs than did performance on the up and middle ramps. There was more variability in completion time (Table 1) and more variability in the number of paw hits (Table 2) even among dogs from the same height category on the down ramp. This variability was likely due to variability in contact behavior, with dogs who came to a complete “2 on 2 off” stop taking much longer on the down ramp than dogs with any other contact behavior (S1 Table). These dogs were also much more likely to have more than 3 front paw hits on the down ramp than dogs who performed another contact behavior (S2 Table). Dogs who performed the complete “2 on 2 off” behavior were also more likely to have more paw hits on the middle ramp than dogs who performed another contact behavior, although mean completion times were similar across all observed contact behaviors for the middle ramp.

Agreement between reviewers (across 41 unique dogs; not all dogs observed by all reviewers) was excellent for time variables (CCC>0.9 for all with mean differences <0.04 seconds). Agreement was also satisfactory or better (Krippendorf’s alpha>0.7) for most categorical variables. There was somewhat less consistency among reviewers in determining if the dog jumped off the down ramp (Krippendorf’s alpha = 0.5).

Discussion

The objective of this study was to describe paw placement patterns for canine athletes completing the dog walk obstacle during canine agility trials. There was a large variation in observed dog walk obstacle performance, both in time to completion and in paw placement patterns. Our hypothesis was therefore rejected, as there was substantial variability in paw placement with no predominant patterns being observed in this population of agility athletes. Although no clear patterns were observed in the current study, the large amount of variation observed with the dog walk obstacle remains an important finding to inform further kinematic and kinetic research and correlate how the variability could relate to the development of injuries. The fact that we were unable to classify dogs based on dog walk performance contrasts with the prior Eicher et. al study that described five distinct paw placement styles in agility dogs performing the weave pole obstacle [9]. Differences in the ability to define paw placement styles in weave pole obstacles and not in the dog walk obstacle could be due to the different kinematics required by the dog to perform each obstacle. The weave pole agility obstacle requires the dog to move in both lateral and forward motions as they move between a series of poles. In contrast, the dog walk obstacle requires the dog to alternate between uphill to downhill movements. They must quickly change from propulsive forces while on the up ramp to braking forces while running or slowing down on the down ramp in order to place a foot within the contact zone.

The large variability in end of obstacle performance on the dog walk may also help explain why consistent patterns were not observed. While there are multiple training techniques for the weave obstacle, ultimately the completion of the obstacle is the same despite varying paw placement patterns. The dog walk obstacle has more variability in end performance behavior depending on whether the handler trains for a running, stopped, or other contact behavior. The results of the current study revealed that only 18% of dogs competing came to a full stop and that many dogs were jumping off the down ramp. This information suggests that a majority of dogs are not consistently performing true stopped contacts, nor are they performing true running contacts where the dog moves across the entire down ramp at a consistent speed. The large number of dogs jumping off the down ramp was unexpected and suggests a need for future studies that include this behavior among the variety of approaches to the contact zone behavior.

There was a fair amount of variation in which paw hit the up ramp first, even though nearly all dogs would be expected to be on their left lead when approaching the dog walk, due to the curve of the tunnel and the presence of the majority of the handlers on the left side of the dog. This may suggest that some dogs are switching their lead leg as they approach the dog walk, in a way that they are preferentially hitting the dog walk with the same leg each time. This is consistent with a previous study by Appelgrein et. al., where it was demonstrated that most dogs entering the A-frame obstacle consistently landed with the same sided forelimb when contacting the A-frame over a series of nine trials [10]. If dogs are preferentially striking both the dog walk and the A-frame obstacle with the same forelimb, this finding may have implications for injury risk and evaluation based on knowledge of a specific dog’s preferred leading limb.

In this study, there was a large degree of variation of paw placement observed both between and within height classes, particularly when performing the down ramp aspect of the dog walk. Many factors, including breed, conformation, speed while completing the obstacle, and training techniques may contribute to the high levels of variation seen in paw placement styles observed. In the study regarding paw placement in dogs performing weave pole obstacles, differences in the relative frequency of the various styles were observed between Border Collies and all other dog breeds even within the same height class [9]. These findings are important to note as differences in breed conformation and size may contribute to the variability observed in the present study, although it is unlikely to be the sole contributor. Additional objective gait analysis techniques are required to identify specific movement patterns during dog walk performance to determine the effect of differences between breeds, morphometric measurements, speed and contact behavior on movement patterns.

Previous studies have hypothesized that there may be an association between injury and performance of specific agility obstacles, naming the dog walk and A-frame obstacles as most often associated with injury based on handler-reported data [35]. The A-frame obstacle requires the dog to ascend and descend a ramp and, like the dog walk, there is a contact zone at the bottom of the down ramp that the dog must place a paw into to successfully complete the obstacle. Unlike the dog walk, the A-frame does not have a flat ramp in the middle of the two ramps and the angle of ascent and descent is steeper, though the obstacle is wider. Both obstacles require the dog to use propulsive forces up the ramp and braking forces down the ramp. Dogs enter both the A-frame and dog walk obstacle at an angle of incline that may act as a source of stress on the joints. A previous study evaluating kinematics of the carpus when entering the A-frame showed that hyperextension of the carpus occurs when dogs enter the a-frame [10], which may contribute to chronic repetitive injuries of the carpus. This study also evaluated whether carpal extension was decreased during A-frame performances when the A-frame was set at a lower incline, and revealed no differences in carpal range of motion [10] at various angles of incline. It is currently unknown how the degree of incline and decline of the dog walk affects kinematics.

An additional study investigating kinematics in working German shepherd dogs completing A-frame obstacles observed that most dogs jumped from the mid-point of the ramp to the ground [11], as these dogs are not trained to complete the obstacle in the same fashion as agility dogs and are not required to place a paw in the contact zone. Surprisingly, this observation was also common in the present study for dogs completing the dog walk, with a large percentage of dogs jumping from the down ramp of the obstacle rather than running off it. The act of jumping higher agility obstacles has been associated with more acute landing angles and an increase in peak vertical forces [11, 12] when landing, which may serve as another source of stress on the joints leading to injuries while completing the a-frame and dog walk obstacles. Given the similarities observed between the two obstacles, further studies regarding paw placement styles of dogs completing the a-frame may be of interest to determine if there is a large amount of variability in paw placement occurring that could contribute to its association with injury and how it compares to the variability seen in dogs completing the dog walk obstacle.

Limitations of this study include the camera angle of the videos observed and the video quality used to observe the canine athletes. The single, non-fixed camera view followed the canine athlete as they crossed the dog walk obstacle and occasionally made it challenging for observation and interpretation of paw placements, most notably for the smaller height categories and for dogs who completed the obstacle very quickly. The quality of video on YouTube is another limitation when compared to other video programs that may have improved video quality and the ability to observe gait patterns frame by frame. The lack of consistent timing devices available in the Youtube videos occasionally required that the reviewer use a manual stopwatch to obtain completion time. This is a limitation because of the potential error inherently involved using a manual timer, however concordance of time measurements among reviewers, even when manually timed, was quite good. Additional limitations to the study included the lack of information available regarding the breed, sex, age and agility experience level of the dogs participating. Each dog was only observed performing the obstacle one time, leaving it unknown how consistent certain dogs are in their paw placement patterns from dog walk to dog walk. The event observed was a national event, which does not account for dogs performing at lower levels of agility and presents a selection bias for dogs performing at higher levels of agility. Because of the higher stakes involved in performing in a national event, handlers may intentionally attempt to increase the speed of their dog, thereby causing more contact faults, which may not be apparent in other competitions or training situations. A final limitation to the study is that only one single course was observed. The current study does not account for different course designs, which may include different angles of entering the dog walk and different handler positions while the dog is completing the obstacle. These differences could alter paw placement patterns and the speed of obstacle completion. To the knowledge of the authors, the current study is the first to attempt to define paw placement patterns used by canine competitors while completing the dog walk obstacle during agility trials in a large group of dogs while also evaluating differences across height classes.

Conclusion

In conclusion, the current study determined that there was a high variability in paw placement in dogs performing the dog walk agility obstacle. The study also found large variability in contact behavior of participating canine athletes. Our hypothesis was therefore rejected as there were no easily observed paw placement patterns found. Currently, canine agility is lacking data regarding definition of movement styles and patterns of obstacle completion. It is also unknown how these movement styles and obstacle completion patterns affect long-term consequences for injury risk and the longevity of the canine athlete. Further studies using kinematic and kinetic data collection are required to better define movement patterns and paw placement styles in canine athletes completing the dog walk obstacle. The high variation of paw placement observed in the current study provides further insight into the challenges that come with definition of canine gait styles during activities and the need for further investigation into this field of study. If gait can be more fully assessed, it may be able to be correlated with injury, which may influence training protocols and injury prevention strategies for these athletes.

Supporting information

S1 Table

(EML)

pone.0299592.s001.eml (11.9KB, eml)
S2 Table

(EML)

pone.0299592.s002.eml (16.4KB, eml)

Acknowledgments

The authors thank additional team members, Amanda Burkhart and Mia Gulan, for their review of a portion of the runs to enable statistical estimate of review consistency.

Data Availability

All of the videos used in this study are publicly available at https://osf.io/24ex6/ (DOI: 10.17605/OSF.IO/24EX6).

Funding Statement

The author(s) received no specific funding for this work.

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Decision Letter 0

Cord M Brundage

2 Jan 2024

PONE-D-23-32065Evaluation of variability in performance by dogs completing the dog walk obstacle in agility competitionPLOS ONE

Dear Dr. Kieves,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process (included below).

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Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: 1. Abstract: Please provide more information about the method!

2. Abstract: Did you compare the date statistically? Did you find significant differences?

3. Introduction: Please provide a little information about the motion analysis of canine with different situations (treadmill, unleashed, leashed)

4. Materials and methods: Why does not have camera on the left side?

5. Materials and methods: How did you detect the initial contact?

6. Materials and methods: How did you measure the height of the withers?

7. Materials and methods: Please provide more information about the statistics!

8. Table 1: p for differences? How did you determine?

9. Table 1: I recommend to move the columns All fogs before the columns O for differences?

10. Discussion: Please repeat the aim of the present research in the first paragraphs (before the hypothesis)

11. Conclusion: Please provide the main contribution, the novelty of the present study.

Reviewer #2: Thank you for your manuscript on performance and paw placement pattern of agility dogs completing the dog walk obstacle. I think these types of studies are important as an initial assessment to help guide further kinetic and kinematic studies, as you suggest. Please find my comments for areas I would like clarification as well as some typographical errors I spotted:

Title: I think the title could be made clearer by adding the phrase “and paw placement patterns” after the word “performance” and saying “in an agility competition” since this is looking at one specific competition/course and not across multiple courses or runs.

Line 29-30: Word missing - “as well associated agility-related injuries.” Should read “as well as associated agility-related injuries.”

Line 35: Missing the word “as” here again - “ as well risk of acute injuries while performing...”

Line 110: Typo “Similarly, the first paw to contact each ramp each ramp was also recorded...” the phrase ‘each ramp’ is written twice.

Results – can you please note how many total videos were analyzed? I am interested to know if the 296 attempts represents all dogs/videos or what number of dogs did not even attempt the obstacle (I see these numbers in the tables later but would be nice to see them in the text). I’d also be interested to know if those dogs that did not attempt the obstacle refused that specific obstacle and therefore that is why it was not attempted, or if there was a reason unrelated to the dog walk that this particular obstacle was not attempted.

I would like to know how the remaining dogs approached the dog walk (as a reader I can guess that the remaining 4% of dogs took the obstacle at the wrong time and that 5% took it with the handler to the right side of the obstacle, but I’d appreciate the clarification, especially if this is not the correct assumption). Where these included in the statistical analysis? I ask because I wonder if the paw strike could be influenced by whether the dog walk was approached in the correct order (from the same orientation after the u-tunnel) and which side the handler was on, and suggest that perhaps these should not be included in the stats.

I would suggest that the number of dogs in each height category be briefly discussed in the text of the results section as currently it is only available in the tables.

Line 144: You mention that the down ramp initial contact could not always be observed in the video. For how many dogs was the down ramp fully observed? (I see this in Table 2 now, but I think it would be nice to include this in the text).

Line 144-145: I am finding this sentence to be a little confusing. I think where I become a little confused by the wording is “...again there is a difference by...” specifically the word again, since what you next say is contradictory to your prior statement rather than in agreement (and thus the word ‘again’ is leading me to be a little confused). I think clarity could be improved by removing the word ‘again’ and starting the remainder of this sentence as a new sentence.

I would consider an additional limitation that this is only looking at a single course. Different course designs (different obstacles before and after dog walk or different angles of entering the obstacle) could alter paw placement patterns and speed of obstacle completion.

**********

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Reviewer #1: No

Reviewer #2: Yes: Christina Montalbano

**********

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PLoS One. 2024 Mar 8;19(3):e0299592. doi: 10.1371/journal.pone.0299592.r003

Author response to Decision Letter 0


26 Jan 2024

Reviewer #1:

1. Abstract: Please provide more information about the method!

Author Response: We have added some clarification to the abstract to indicate that this was an online video review to clarify the methodology. The primary statistical analysis was descriptive, so we have not specifically included that in the abstract. However, please let us know if there are additional details of our methods that should be included in the abstract. (Lines 16-19)

2. Abstract: Did you compare the date statistically? Did you find significant differences?

Author Response: We assume this comment refers to the comparisons between height classes referenced in the abstract. As noted in the text of our methods, our primary objective of this study was descriptive, so our results in the abstract reflect this descriptive goal. We have added the word “qualitatively” to indicate this in the abstract. (Line 19)

3. Introduction: Please provide a little information about the motion analysis of canine with different situations (treadmill, unleashed, leashed)

Author Response: The authors are unsure what additional information the reviewer feels would be important to include in the introduction regarding motion analysis. If you could clarify the authors would be happy to consider amending the introduction in future versions of the manuscript.

4. Materials and methods: Why does not have camera on the left side?

Author Response: Thank you for this question. This study was done using a recording of the event created by 4LeggedFlix. We did not select the camera placement and utilized the one view that was available for this study. We have added clarification of this point to the text. (Lines 94-95)

5. Materials and methods: How did you detect the initial contact?

Author Response: Initial contact with the obstacle was observed by video review while watching the video at reduced speed. We have added clarification to the text regarding this. (Line 100)

6. Materials and methods: How did you measure the height of the withers?

Author Response: The height of the withers was inferred from the dog’s jump height class measured and provided by the UKI program directory that was available online. We have clarified this point in the text. (Lines 128-130)

7. Materials and methods: Please provide more information about the statistics!

Author Response: We have added additional clarification of how p for difference was determined for the time variables in table 1 (lines 137-139). We otherwise believe the description of the statistics used is complete.

8. Table 1: p for differences? How did you determine?

Author Response: These were multivariate Wald tests following linear regression with robust standard errors. This has been clarified in the methods. (Lines 137-139)

9. Table 1: I recommend to move the columns All fogs before the columns O for differences?

Author Response: Thank you for this suggestion. Based on this suggestion, we have moved the “all dogs” to the first column for readability.

10. Discussion: Please repeat the aim of the present research in the first paragraphs (before the hypothesis)

Author Response: Thank you for the suggestion. A sentence was added to the discussion to clarify the aim of the study. (Lines 234-235)

11. Conclusion: Please provide the main contribution, the novelty of the present study.

Author Response: Thank you for the suggestion. We have added text to the conclusion to provide the main contribution and importance of the study. (Lines 350-353)

Reviewer #2: Thank you for your manuscript on performance and paw placement pattern of agility dogs completing the dog walk obstacle. I think these types of studies are important as an initial assessment to help guide further kinetic and kinematic studies, as you suggest. Please find my comments for areas I would like clarification as well as some typographical errors I spotted:

Title: I think the title could be made clearer by adding the phrase “and paw placement patterns” after the word “performance” and saying “in an agility competition” since this is looking at one specific competition/course and not across multiple courses or runs.

Author Response: Thank you for the suggestion, this change has been made.

Line 29-30: Word missing - “as well associated agility-related injuries.” Should read “as well as associated agility-related injuries.”

Author Response: Thank you for the careful read and noticing this error. This has been corrected. (Line 30)

Line 35: Missing the word “as” here again - “ as well risk of acute injuries while performing...”

Author Response: Thank you for noticing this error, it has been corrected. (Line 36)

Line 110: Typo “Similarly, the first paw to contact each ramp each ramp was also recorded...” the phrase ‘each ramp’ is written twice.

Author Response: Thank you for noticing this error, it has been corrected. (Line 112)

Results – can you please note how many total videos were analyzed? I am interested to know if the 296 attempts represents all dogs/videos or what number of dogs did not even attempt the obstacle (I see these numbers in the tables later but would be nice to see them in the text). I’d also be interested to know if those dogs that did not attempt the obstacle refused that specific obstacle and therefore that is why it was not attempted, or if there was a reason unrelated to the dog walk that this particular obstacle was not attempted.

Author Response: Thank you for these thoughtful comments. All videoed runs of the course were reviewed; however, we did not specifically capture if a dog started the course, but did not attempt the dog walk obstacle. We believe this was rare, but do not have the exact data to provide. The 296 represents all dogs who attempted the course and also attempted the dog walk obstacle (defined as putting at least one paw on the obstacle). We have reworded the first line of the results to help clarify. (Lines 153-154)

I would like to know how the remaining dogs approached the dog walk (as a reader I can guess that the remaining 4% of dogs took the obstacle at the wrong time and that 5% took it with the handler to the right side of the obstacle, but I’d appreciate the clarification, especially if this is not the correct assumption). Where these included in the statistical analysis? I ask because I wonder if the paw strike could be influenced by whether the dog walk was approached in the correct order (from the same orientation after the u-tunnel) and which side the handler was on, and suggest that perhaps these should not be included in the stats.

Author Response: Thank you for the suggestion. We have added the information about approaching the dog walk in flow and explicitly about handler side to the results (lines 155-157). We agree that paw strike could be influenced by approach (although here all but two dogs took the u-shaped tunnel first) and by handler side. However, our goal was to describe the patterns observed completing the obstacle within a course; not specifically to describe patterns observed with a prescribed approach and prescribed handler side so our primary analysis included all dogs. We note that restricting the analysis to dogs who took the dog walk in flow and with the handler on the left (n=270) showed very similar patterns to the full sample. We have added to the discussion the idea that handler position and approach may impact paw strike patterns and completion times. (Lines 335-338)

I would suggest that the number of dogs in each height category be briefly discussed in the text of the results section as currently it is only available in the tables.

Author Response: We have added text to the results to include this information. (Lines 161-163)

Line 144: You mention that the down ramp initial contact could not always be observed in the video. For how many dogs was the down ramp fully observed? (I see this in Table 2 now, but I think it would be nice to include this in the text).

Author Response: Thank you for the suggestion. We have added the number of dogs for whom the down ramp initial contact was observed (262) to the text. (Line 169)

Line 144-145: I am finding this sentence to be a little confusing. I think where I become a little confused by the wording is “...again there is a difference by...” specifically the word again, since what you next say is contradictory to your prior statement rather than in agreement (and thus the word ‘again’ is leading me to be a little confused). I think clarity could be improved by removing the word ‘again’ and starting the remainder of this sentence as a new sentence.

Author Response: Thank you for the suggestion. A new sentence was created to make this clearer. (Lines 169-170)

I would consider an additional limitation that this is only looking at a single course. Different course designs (different obstacles before and after dog walk or different angles of entering the obstacle) could alter paw placement patterns and speed of obstacle completion.

Author Response: Thank you for the suggestion. A statement was added to the discussion regarding this limitation. (Lines 334-336)

Attachment

Submitted filename: Author Response Final.docx

pone.0299592.s004.docx (21.9KB, docx)

Decision Letter 1

Cord M Brundage

13 Feb 2024

Evaluation of variability in performance and paw placement patterns by dogs completing the dog walk obstacle in an agility competition

PONE-D-23-32065R1

Dear Dr. Kieves,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Cord M. Brundage, D.V.M., Ph.D.

Academic Editor

PLOS ONE

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: (No Response)

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Thank you for your answer, the correction, extension is enough for me. I recommend the corrected version for acceptance.

Reviewer #2: (No Response)

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: Yes: Christina Montalbano

**********

Acceptance letter

Cord M Brundage

26 Feb 2024

PONE-D-23-32065R1

PLOS ONE

Dear Dr. Kieves,

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team.

At this stage, our production department will prepare your paper for publication. This includes ensuring the following:

* All references, tables, and figures are properly cited

* All relevant supporting information is included in the manuscript submission,

* There are no issues that prevent the paper from being properly typeset

If revisions are needed, the production department will contact you directly to resolve them. If no revisions are needed, you will receive an email when the publication date has been set. At this time, we do not offer pre-publication proofs to authors during production of the accepted work. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few weeks to review your paper and let you know the next and final steps.

Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

If we can help with anything else, please email us at customercare@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Cord M. Brundage

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Table

    (EML)

    pone.0299592.s001.eml (11.9KB, eml)
    S2 Table

    (EML)

    pone.0299592.s002.eml (16.4KB, eml)
    Attachment

    Submitted filename: Major Revision - Response to Reviewers.docx

    pone.0299592.s003.docx (18.4KB, docx)
    Attachment

    Submitted filename: Author Response Final.docx

    pone.0299592.s004.docx (21.9KB, docx)

    Data Availability Statement

    All of the videos used in this study are publicly available at https://osf.io/24ex6/ (DOI: 10.17605/OSF.IO/24EX6).


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