The magnitude of muscular activation of four canine forelimb muscles in dogs performing two agility-specific tasks

Management of Injuries in Agility Dogs

Agility is a physically demanding sport, and injuries are common. An understanding of the common clinical presentations, frequent injuries, and risk factors for injury is critical when seeing this population of patients in practice. Shoulder injuries and other soft tissue injuries including iliopsoas muscle strains are commonly seen. The Border Collie seems to be at higher risk of developing agility-related injuries. The key to rehabilitation of the agility dog is accurate and expedient diagnosis of the injury, which often involves advanced diagnostics such as musculoskeletal ultrasound, arthroscopy, and/or MRI.

Effects of jump height on forelimb landing forces in border collies

Objective

The objective of this study was to evaluate the effects of jump height on the landing forces of dogs.

Animals

Client-owned Border Collies experienced in agility competition, n = 9.

Procedures

The study involved client owned border collies with the same AKC standard jump height of 20 inches and preferred height of 16 inches. Standard height is based upon the height of the dog at the withers, with preferred height referred to as reduction in jump height by one level due to injury or age. An AKC regulation bar jump was placed over a previously validated pressure sensitive walkway (PSW). The peak force (%BW) and peak contact pressure (kPa) of the leading and trailing forelimbs were evaluated for all dogs.

Results

There was no significant difference in landing force between the two jump heights for either peak force as a percentage of body weight or peak contact pressure when evaluated in both leading and trailing forelimbs.

Conclusions and clinical relevance

Our findings demonstrated no significant difference in active landing forces of peak contact pressure and peak force on the forelimbs of dogs when jumping at a standard jump height vs. a preferred jump height when controlling for velocity in dogs performing a single running bar jump. These results suggest that the recommendation of decreasing jump height for older animals or injured animals may not provide a significant decrease in the impact on the forelimbs. It is likely that other factors contribute to the total forelimb kinematics picture during competition. Veterinarians and trainers should consider additional ways to decrease impact for canine athletes as they recover from injury.

Structural and pathological changes in the enthesis are influenced by the muscle contraction type during exercise

Mechanical stress is involved in the onset of sports-related enthesopathy. Although the amount of exercise undertaken is a recognized problem during disease onset, changes in muscle contraction type are also involved in the increase in mechanical stress during exercise. This study aimed to clarify the effects of increased mechanical stress associated with muscle contraction type and amount of exercise on enthesis. Twenty mice underwent treadmill exercise, and the muscle contraction type and overall load during exercise were adjusted by varying the angle and speed conditions. Histological analysis was used to the cross-sectional area of the muscle; area of the enthesis fibrocartilage (FC), and expression of inflammation-, degeneration-, and calcification-related factors in the FC area. In addition, the volume and structure of the bone and FC area were examined using microcomputer imaging. Molecular biological analysis was conducted to compare relative expression levels of inflammation and cytokine-related factors in tendons. The Overuse group, which increased the amount of exercise, showed no significant differences in parameters compared to the sedentary mice (Control group). The mice subjected to slow-speed downhill running (Misuse group) showed pathological changes compared to the Control and Overuse groups, despite the small amount of exercise. Thus, the enthesis FC area may be altered by local mechanical stress that would be increased by eccentric muscle contraction rather than by mechanical stress that increases with the overall amount of exercise. Clinical Significance: The muscle contraction type might be more involved in the onset of sports-related enthesopathy rather than the amount of exercise.

Conditioning Dogs for an Active Lifestyle

The aim of conditioning is to remodel body tissues in preparation for the physical demands of activity. Body tissues need strength to produce and withstand the forces generated during movement. Body tissues remodel in response to load, for example, training can remodel and increase the size of tendons, but this takes time. Training does more than just strengthening tissues; it also improves tissue response to exercise and recovery time. The National Sports Medicine Institute in the United Kingdom states "regular exercise increases muscle tone, facilitates good circulation, improves strength, agility and flexibility and improves the rate of waste product disposal."

Internet Survey of Risk Factors Associated With Training and Competition in Dogs Competing in Agility Competitions

Objective: To describe risk factors associated with training and competition in relation to frequency and severity of injuries experienced by agility dogs.

Procedures: An internet-based survey collected data on competition level variables and training level variables. The primary outcome was history of any injury and a secondary outcome considered history of severe injury (injury lasting > 3 months). Logistic regression was used to estimate associations and final models were obtained via backward selection to identify the strongest associations within variables.

Results: There were 4,197 dogs included in this analysis. Injury was reported for 1,737 (41.4%) dogs and severe injury was reported for 629 (15.0%). In the model with competition level factors, jumping 4” (OR: 1.50) or 2–4” (OR: 1.31) over shoulder height compared to jumping 0–2” lower and competing at national events was associated with increased injury risk, while competing 6+ times on rubber matting was associated with lower risk (OR: 0.62). Training level variables associated with injury risk were age starting jump, teeter, and weave training, with the highest risk observed for dogs starting jump training between 3 and 18 months but starting weave and teeter training after 18 months of age.

Conclusion and Clinical Relevance: Many variables thought to be associated with injury risk were not significant in the final model. Starting jump training at an earlier age was associated with greater risk of injury relative to starting after 18 months. It is possible that the high impact of jump training before skeletal maturity may increase the risk of injuries or musculoskeletal conditions. The increased risk of injury in dogs that jump 2–4, or 4+ inches higher than shoulder height may be due to increased biomechanical forces during takeoff and landing. Faster dogs may be at higher risk of injury; handlers planning competition around big events or competing at the national level are likely to have faster dogs, and may be less likely to compete on rubber matting. These data provide valuable current insight into the possible effects that training and competition variables may have on injury risk in agility dogs.

Part II of Finnish Agility Dog Survey: Agility-Related Injuries and Risk Factors for Injury in Competition-Level Agility Dogs

Simple Summary

Agility dogs can get injured during sports performance. Only a few factors have been linked to risk for injury. Through an online questionnaire, information was collected of more than 860 Finnish competition-level agility dogs. Of these dogs, 119 (14%) had suffered an injury in agility during calendar year 2019. Front limbs were most commonly injured. Typically, the injury presented as lameness. In general, dogs regained their performance level in four weeks, but 10% of injured dogs retired from the sport due to the injury. Dogs with multiple previous agility-related injuries or a diagnosis of lumbosacral transitional vertebra had higher odds of getting injured. Other common factors among the injured dogs included older age when starting course-like training and more than two agility-training sessions a week. A moderate number of monthly competition runs and an A-frame performance technique had lower odds of injury. This study identified new risk factors for injury in agility. This information can be used to improve the welfare of agility dogs.

Abstract

Dog agility is associated with a risk for sport-related injuries, but few risk factors for injury are known. A retrospective online questionnaire was used to collect data on 864 Finnish competition-level agility dogs—including 119 dogs (14%) with agility-related injury during 2019. Data included injury details, health background, experience in agility, and sport and management routines prior to the injury. Risk factors for injury were evaluated with multivariate logistic regression. The rate of competition-related injuries was 1.44 injuries/1000 competition runs. The front limb was injured in 61% of dogs. In 65% of dogs, the injury presented as lameness. The main risk factors for agility-related injury during 2019 were multiple previous agility-related injuries (OR 11.36; 95% CI 6.10–21.13), older age when starting course-like training (OR 2.04 per one year increase; 95% CI 1.36–3.05), high training frequency, diagnosis of lumbosacral transitional vertebra, and physiotherapy every two to three months compared with never. The most important protective factors were moderate competition frequency and A-frame performance technique. These associations do not confirm causality. We identified new risk factors for injury in agility. This information can be used to improve the welfare of agility dogs.

Part I of Finnish Agility Dog Survey: Training and Management of Competition-Level Agility Dogs

Knowledge regarding training, competition, and management routines of agility dogs is lacking. Through a retrospective online questionnaire, Finnish owners and handlers of 745 competition-level agility dogs provided information on training routines and management of these dogs during one year free of agility-related injuries. Competition routines were collected from the national competition results database. Most dogs trained agility 1-2 times a week, with a median active training time of 18 min a week. Dogs competed in a median of 2.1 runs per month at a speed of 4.3 m/s. Common field surfaces were different types of artificial turfs and dirt surface. Warm-up and cool-down were established routines, and 62% of dogs received regular musculoskeletal care. Moreover, 77% of dogs underwent conditioning exercises, but their frequency was often low. Additionally, dogs were walked for a median of 1.5 h daily. Pearson's chi-squared and Kruskal-Wallis tests were used to evaluate the association between a dog's competition level and training and competition variables. A dog's competition level was associated with competition (p < 0.001) and training frequency (p < 0.001); dogs at higher levels compete more but train less than dogs at lower levels. This study provides information on training, competition, and management routines of competing agility dogs.

Efficacy of Serial Ultrasonographic Examinations in Predicting Return to Play in Agility Dogs with Shoulder Lameness

The aim of this study is to investigate the use of shoulder ultrasound as a method of predicting the likelihood of returning to competition in agility dogs with shoulder teno-muscular injuries after a standardised rehabilitation protocol. Thirty-two agility dogs with a clinical and ultrasonographic diagnosis of shoulder teno-muscular injury were included in a prospective study with physical and ultrasound examinations at the time of diagnosis (T0) and at two (T2), four (T4) and six (T6) months; during this period, the dogs received rehabilitation treatments. The endpoint of the study was to obtain information regarding participation in agility competitions 12 months after diagnosis, based on telephone interviews with the owners. The clinical lameness score (CLS) and the ultrasound lesion score (ULS) were used as outcome measurements. The CLS indicated partial recovery from a shoulder injury at T2 (78%), while the ULS indicated no satisfactory recovery at T2 in any patient. At 4 months, the CLS alone was not a valuable predictor of full recovery from a shoulder injury in agility dogs. Relative Risk indicated that, at T2, ultrasound was 23.8 times more valuable in identifying a shoulder lesion as compared to clinical lameness score (CLS), and it was 2.53 times more valuable at T4.

Internet-based survey of the frequency and types of orthopedic conditions and injuries experienced by dogs competing in agility

OBJECTIVE

To describe the frequency and types of injuries experienced by dogs competing and training in agility and identify breed and geographic differences in frequency and types of injuries.

SAMPLE

Surveys completed by owners of 4,701 dogs.

PROCEDURES

The study involved an internet-based survey. Participants were asked whether their dog had ever had an injury that kept it from participating in agility for > 1 week and, if so, to identify the location and type of injury.

RESULTS

Owners of 1,958 (41.7%) dogs reported that their dogs had experienced an injury. The most common injury locations were the shoulder region (n = 589 [30.1% of all dogs with an injury]) and iliopsoas muscle (380 [19.4%]). The percentage of Border Collies sustaining an injury (549/1,052 [51.9%]) was significantly higher than percentages of other breeds. Percentage of dogs that sustained an injury varied by country, with the highest percentage reported in Australia (93/174 [53.4%]) and lowest percentage reported in the US (1,149/2,889 [39.8%]).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that, among dogs competing and training in agility, injuries to the shoulder region were substantially more common than injuries in other anatomic locations, with iliopsoas muscle injuries second most common. The frequency and types of injuries varied among breeds and geographic regions. Findings may help guide clinical evaluations when agility dogs are seen in clinical practice for performance issues or lameness. Further studies regarding regional differences in injury rates are required.

Ultrasonographic diagnosis of bilateral partial rupture of the infraspinatus muscle in a racing greyhound

Athletic dogs are more susceptible to musculoskeletal disorders, especially in the muscles or tendons surrounding the shoulder joint. In this report, we describe a case of partial bilateral rupture of the infraspinatus muscle, an unusual injury. Clinical signs included lameness of the left thoracic limb after training. On physical examination, there was discomfort on bilateral palpation in the infraspinatus fossa region. The main clinical suspicion was partial rupture or myositis of the infraspinatus muscle (IF). Ultrasound examination of the region revealed the presence of hypoechoic areas intermingling the muscle fibers in a deeper and distal region of the infraspinatus muscle, compatible with edema or bilateral intramuscular hematoma (left +++, right ++) and integrity of the fascia. The findings were characterized as a partial rupture of the musculature. A detailed physical examination associated with ultrasound examination is essential for early diagnosis and therapeutic management. Although no other reports of partial rupture of the IF have been found, partial or complete rupture of muscle fibers in sport dogs is frequent. Early diagnosis prevents the development of contractures due to the institution of therapy before the fibrous process is established and improves prognosis.

Technique description: Incisionless ultrasound-assisted biceps tenotomy in dogs

Background:

Bicipital tendinitis and/or tendinopathy is a common cause of forelimb lameness in dogs, particularly in larger and more active patients. Although conservative treatment aimed at resolving discomfort and preserving the tendon remains the primary therapeutic goal, in certain cases it is necessary to surgically transect the tendon to eliminate pain and lameness. Transection of the tendon can be performed by open arthrotomy, arthroscopically, or percutaneously using a scalpel blade. This paper examines the utility of a modified percutaneous approach using a hypodermic needle in place of a scalpel blade, under ultrasound-guided assistance.

Aim:

To develop and describe a surgical technique for performing a percutaneous biceps tenotomy using a hypodermic needle under ultrasound guidance

Method:

The technique was piloted using the shoulders of 12 cadaver dogs initially and once developed, then applied to another 12 cadavers. The final procedure was performed on a total of 22 shoulders. Assessments were recorded on time to complete the procedure, completeness of bicipital tendon transection, and presence of any iatrogenic damage to associated joint structures.

Results:

Procedure time averaged fewer than 2 minutes. Complete transection was achieved in 20 out of 22 of the shoulders, with evidence of incomplete transection discernable by ultrasound imaging in the remaining two shoulders. One cadaver shoulder experienced iatrogenic damage secondary to incorrect hypodermic needle angulation.

Conclusion:

Percutaneous biceps tenotomy using a hypodermic needle is an efficient and straightforward procedure. The lack of a surgical incision makes it the least invasive technique devised so far. Ultrasound imaging allows the practitioner to assess the completeness of the transection increasing precision.

Comparative Kinematic Analysis of Hurdle Clearance Technique in Dogs: A Preliminary Report

Simple Summary

Hurdle jumping is part of the increasingly popular canine agility competition. Although the jumping characteristics of agility dogs have been examined in recent years, there is currently a lack of data related to the suspension phase. The purpose of the present study was to investigate the biomechanics of the suspension phase of the agility jump and to analyze the kinematic differences in dogs with different jumping abilities. Two groups of dogs competing at different skill levels and assessed as excellent jumpers and less-skilled jumpers, respectively, were analyzed and compared. Excellent jumpers showed longer and faster jumps with flatter jump trajectories than less-skilled jumpers. In less-skilled jumpers, the distance in front of the hurdle was notably greater than the distance behind it, while the difference between these two distances was less in excellent jumpers. Length and duration of the jump, maximal height of the jumping trajectory, take-off and landing distances to the hurdle, time of occurrence of maximal jump height, and time of change in back orientation essentially defines the suspension phase of the agility jump. This study presents preliminary evidence that the kinematic characteristics of hurdle clearance are different in excellent jumper dogs and in less-skilled jumper dogs.

Abstract

Although the jumping characteristics of agility dogs have been examined in recent years, there is currently a lack of data related to the suspension phase. The purpose of the present study was to investigate the biomechanics of the suspension phase of the agility jump and to analyze the kinematic differences in dogs with different jumping abilities. Two groups of dogs of the same height category (large dogs) competing at different skill levels and assessed as excellent jumpers (n = 4) and less-skilled jumpers (n = 3), respectively, were analyzed and statistically compared. Excellent jumpers showed longer and faster jumps with flatter jump trajectories than less-skilled jumpers. In less-skilled jumpers, the distance in front of the hurdle was notably greater than the distance behind it, while the difference between these two distances was less in excellent jumpers. Length and duration of the jump, maximal height of the jumping trajectory, take-off and landing distances to the hurdle, time of occurrence of maximal jump height, and time of change in back orientation essentially defines the suspension phase of the agility jump. This study presents preliminary evidence that the kinematic characteristics of hurdle clearance are different in excellent jumper dogs and in less-skilled jumper dogs.

Surface Electromyography of the Vastus Lateralis, Biceps Femoris, and Gluteus Medius in Dogs During Stance, Walking, Trotting, and Selected Therapeutic Exercises

Objective: The objective of the study reported here was to evaluate the muscle activity patterns of the vastus lateralis (VL), biceps femoris (BF), and gluteus medius (GM) during stance, walking, trotting, and selected therapeutic exercises in clinically sound, healthy dogs. Our hypothesis was that the muscle activity during all exercises would differ from muscle activity at the stance. Methods: Surface electromyography of the selected muscles was performed during stance, walking, trotting, elevation of forelimbs on a platform, elevation of forelimbs on a platform with hindlimbs on an inflatable balance device, stepping up onto and over an obstacle, standing on a wobble board, dancing backwards, and wearing a leg weight at the walk and the trot. The maximal and mean muscle amplitude (μV) reflecting activity during several motion cycles were compared among the exercises. Results: Mean EMG amplitude of the BF was significantly higher in all exercises (p < 0.05) in comparison to stance. Mean EMG amplitude of the VL was significantly higher (p < 0.05) during walking, trotting, dancing backwards, stepping up and over an obstacle, and at a trot with a leg weight as compared to stance. Mean EMG amplitude of the GM was significantly higher (p < 0.05) during trotting, at a walk and a trot with a leg weight, standing on a wobble board, stepping up and over an obstacle, and dancing backwards when compared to stance. Of the studied exercises, dancing backwards increased the mean EMG amplitude of the BF and GM to the largest degree. Stepping up and over an obstacle increased the mean EMG amplitude of the VL to the largest degree. Conclusion: Compared to stance, the majority of therapeutic exercises examined increased muscle activity to varying degrees in the BF, VL, and GM. Our results may help clinicians to choose specific exercises to target specific muscles during conditioning, strengthening and rehabilitation.

Neurological functional evaluation based on accurate motions in big animals with traumatic brain injury

An accurate and effective neurological evaluation is indispensable in the treatment and rehabilitation of traumatic brain injury. However, most of the existing evaluation methods in basic research and clinical practice are not objective or intuitive for assessing the neurological function of big animals, and are also difficult to use to qualify the extent of damage and recovery. In the present study, we established a big animal model of traumatic brain injury by impacting the cortical motor region of beagles. At 2 weeks after successful modeling, we detected neurological deficiencies in the animal model using a series of techniques, including three-dimensional motion capture, electromyogram and ground reaction force. These novel technologies may play an increasingly important role in the field of traumatic brain injury diagnosis and rehabilitation in the future. The experimental protocol was approved by the Animal Care and Use Committee of Logistics University of People’s Armed Police Force (approval No. 2017-0006.2).

Peak forelimb ground reaction forces experienced by dogs jumping from a simulated car boot

Many dog owners allow their pets to jump out of a car boot; however, to date, there has been no study that has investigated whether this places dogs at risk of injury. The aim of this study was to investigate the relationship between height and peak vertical ground reaction force (vGRF) in static start jumps. Fifteen healthy adult dogs performed three jumps from a platform that represented common vehicle boot sill heights (0.55, 0.65, 0.75 m), landing on a single force platform. Kinetic data (mediolateral (Fx), craniocaudal (Fy) and vertical (Fz)) were normalised for body weight and analysed via a one-way repeated analysis of variance (ANOVA) and pairwise post hoc tests with a Bonferroni correction applied. There was a significant difference in peak forelimb vGRF between both the 0.55 m (27.35±4.14 N/kg) and the 0.65 m (30.84±3.66 N/kg) platform (P=0.001) and between the 0.65 and 0.75 m (34.12±3.63 N/kg) platform (P=0.001). There was no significant difference in mediolateral or craniocaudal forces between the heights examined. These results suggest that allowing dogs to jump from bigger cars with a higher boot sill may result in augmented levels of loading on anatomical structures. Further research is required to investigate the kinematic effects of height on static jump-down and how peak forelimb vGRF relates to anatomical loading and subsequent injury risk.