Bioimpedance analysis (BIA) is a well‐known and tested method for body mass and muscular health assessment. Multi‐frequency BIA (mfBIA) equipment now makes it possible to assess a particular muscle as a whole, as well as looking at a muscle at the fiber level. The aim of this study was to test the hypothesis that mfBIA can be used to assess the anatomical, physiological, and metabolic state of skeletal muscles. mfBIA measurements focusing on impedance, resistance, reactance, phase angle, center frequency, membrane capacitance, and both extracellular and intracellular resistance were carried out. Eight healthy human control subjects and three selected cases were examined to demonstrate the extent to which this method may be used clinically, and in relation to training in sport. The electrode setup is shown to affect the mfBIA parameters recorded. Our recommendation is the use of noble metal electrodes in connection with a conductance paste to accommodate the typical BIA frequencies, and to facilitate accurate impedance and resistance measurements. The use of mfBIA parameters, often in conjunction with each other, can be used to reveal indications of contralateral muscle loss, extracellular fluid differences, contracted state, and cell transport/metabolic activity, which relate to muscle performance. Our findings indicate that mfBIA provides a noninvasive, easily measurable and very precise momentary assessment of skeletal muscles. E. M. Bartels, E. R. Sørensen, A. P. Harrison, # Multi‐frequency bioimpedance in human muscle assessment {#article-title-2}, Physiol Rep, 3 (4), 2015, e12354, doi: 10.14814/phy2.12354

Few studies have investigated the physiological parameters of endurance horses in Scandinavia. Hence, this two race study has focused on the effects of endurance racing in terms of equine clinicopathological blood parameters, heart score, and fluid use. Race A involved 15 horses (120 km). Two pre- and one post-race blood samples were taken, body condition score was assessed in triplicate pre-race, and an ECG was used to determine heart score. Race B involved 16 horses (65–120 km). One pre- and two post-race blood samples were taken. For both races, horse data as well as fluid intake estimates and cooling water were noted. Race A showed that blood haematocrit, albumin, sodium, and triglycerides increased significantly with endurance racing, whilst chloride, glucose, iron, and potassium decreased significantly. In race B, blood creatinine, cholesterol, and inorganic phosphate continued to increase significantly during the first post-race sampling period compared to pre-race levels, whilst iron, which decreased significantly during the race, increased significantly over the two post-race sampling periods. It is concluded that whilst no correlation between heart score and speed was observed, a significant correlation exists between experience and changes in blood parameters with endurance racing and between fluid intake and average speed.

Fascia in the veterinary sciences is drawing attention, such that physiotherapists and animal practitioners are now applying techniques based on the concept of fascia studies in humans. A comprehensive study of fascia is therefore needed in animals to understand the arrangement of the fascial layers in an unguligrade horse and a digitigrade dog. This study has examined the difference between the horse and the dog fascia at specific regions, in terms of histology, and has compared it with the human model. Histological examinations show that in general the fascia tissue of the horse exhibits a tight and dense composition, while in the dog it is looser and has non‐dense structure. Indeed, equine fascia appears to be different from both canine fascia and the human fascia model, whilst canine fascia is very comparable to the human model. Although regional variations were observed, the superficial fascia (fascia superficialis) in the horse was found to be trilaminar in the trunk, yet multilayered in the dog. Moreover, crimping of collagen fibers was more visible in the horse than the dog. Blood vessels and nerves were present in the loose areolar tissue of the superficial and the profound compartment of hypodermis. The deep fascia (fascia profunda) in the horse was thick and tightly attached to the underlying muscle, while in the dog the deep fascia was thin and loosely attached to underlying structures. Superficial and deep fascia fused in the extremities. In conclusion, gross dissection and histology have revealed species variations that are related to the absence or presence of the superficial adipose tissue, the retinacula cutis superficialis, the localization and amount of elastic fibers, as well as the ability to slide and glide between the different layers. Further research is now needed to understand in more detail whether these differences have an influence on the biomechanics, movements and proprioception of these animals.

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.