The impact of water depth and speed on muscle fiber activation of healthy dogs walking in a water treadmill

Abstract

Background Water treadmills are frequently used in the rehabilitation of dogs, for example with the purpose of re-building muscular strength after surgery. However, little is known about how different water depths and velocities affect the muscular workload during aquatic locomotion. This study used acoustic myography to assess hind limb muscle fiber activation in 25 healthy large-breed dogs walking in a water treadmill. Acoustic myography sensors were attached to the skin over the vastus lateralis of the quadriceps and the biceps femoris muscles. The dogs walked at two velocities (30 and 50 m/min) and four water depths: bottom of the pads, hock, stifle and mid-femur. Acoustic myograph signals were analyzed for changes in three muscle function parameters: efficiency/coordination (E-score) and spatial (S-score) and temporal (T-score) summation. Results Differences between E, S, and T were statistically significant compared across different speeds (30, 50) and water levels (0, 1, 2, 3) using a one-way ANOVA with multiple comparisons (Tukey; Geisser-Greenhouse correction) as well as a two-tailed one sample t-test. At 50 m/min in water at the mid-femur, the biceps femoris was less efficient (P < 0.001) and recruited more fibers (P = 0.01) at a higher firing rate (P = 0.03) compared to working in shallower water, while the vastus lateralis was also less efficient (P < 0.01), but spatial and temporal summation did not change significantly. At 30 m/min, biceps efficiency was reduced (P < 0.01) when water was at the mid-femur compared to the bottom of the pads level. Walking in stifle- or hock-deep water did not show increased muscle activation for either muscle compared to walking in water at the bottom of the pads. Conclusion More muscle activation was required to walk in water at a depth at the level of the mid-femur compared to shallower water, and this exercise was more demanding for the biceps femoris, a muscle engaged in propulsion, than for vastus lateralis. These findings may help practitioners towards making more precise rehabilitation protocols.

Physiotherapeutic Strategies and Their Current Evidence for Canine Osteoarthritis

“…Joint kinematics and stride parameter differ depending on whether dogs are swimming or walking at different water levels on an underwater treadmill [ 102 , 103 , 104 ]. Recent underwater treadmill studies on healthy dogs reflect that vastus lateralis, biceps femoris and longissimus dorsi muscle activation is affected by water level [ 105 , 106 ].…”

Use of acoustic myography to evaluate forelimb muscle function in retriever dogs carrying different mouth weights

“…The piezoelectric AMG sensor is thin and minimizes interference from lateral movement on the skin as it only measures sound waves in one direction ( 11 , 13 ). AMG has been used in dogs in previous studies to evaluate muscle contractions ( 12 – 14 ). The AMG equipment records the sound and calculates three parameters: the E, S, and T-scores with a scale of 0–10.…”

“…The AMG equipment records the sound and calculates three parameters: the E, S, and T-scores with a scale of 0–10. The E-score (efficiency score) reflects coordination of the muscle and muscle activity in relation to inactivity in units of seconds ( 14 ). A decrease in E-score while the muscle is working reflects more contraction time vs. relaxation indicating early muscle fatigue ( 11 ).…”

“…The S-score (spatial summation score) reflects signal amplitude as measured in millivolts (mV) ( 11 ). A low amplitude during work, indicates that the work is easy, therefore the S-score will be high ( 13 , 14 ). T-score (temporal summation) is the frequency of muscle fiber recruitment in Hertz (Hz).…”

“…T-score (temporal summation) is the frequency of muscle fiber recruitment in Hertz (Hz). During very hard work more muscle fibers are recruited, increasing the frequency, resulting in a lower T-score ( 13 , 14 ).…”