A Systematic Review of the Biomechanical Effects of Harness and Head-Collar use in Dogs

The number of dogs in the UK is on the rise, as are canine sports involving the use of a harness to allow the dog to pull against an interface in the same way as a husky might pull a sled. Service dogs and those involved in essential work commonly wear a harness throughout their working lives, yet little is understood regarding the biomechanical impact of their use. This systematic review was conducted to review reported evidence of the biomechanical effects of harness and head collar (Halti) use in dogs. Searches were applied covering 1910 to 2018 on the following databases: PubMed, Web of Science and Writtle Discovery. Three publications were identified as suitable which were then critically evaluated using predefined criteria and ARRIVE based guidelines for bias assessment. Only one was considered to provide the most reliable data regarding the influence of harnesses on gait, whilst the remainder were considered to suffer a variety of issues including poor sample size, repeatability and study execution. The most appropriate study found that wearing a chest strap harness reduced shoulder extension in both walk and trot by up to 8° of movement, whilst a Y-shaped harness commonly marketed as non-restrictive reduced shoulder extension by up to 10° of movement, suggesting that the use of harness type restraints can affect canine gait, whereas no studies were found relating to the biomechanical effects of head-collar usage.