Colder water temperatures may be more effective in the treatment of exercise-induced muscle damage and injury rehabilitation by virtue of greater reductions in muscle temperature and not muscle blood flow.

Cold-Water Mediates Greater Reductions in Limb Blood Flow than Whole Body Cryotherapy.http://researchonline.ljmu.ac.uk/5455/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively. Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Users may download and/or print one copy of any article(s) in LJMU Research Online to facilitate their private study or for non-commercial research. You may not engage in further distribution of the material or use it for any profit-making activities or any commercial gain.The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription. Purpose: Cold-water immersion (CWI) and whole body cryotherapy (WBC) are 2 widely used recovery methods in an attempt to limit exercise-induced muscle damage, 3 soreness and functional deficits after strenuous exercise. The aim of this study was to 4 compare the effects of ecologically-valid CWI and WBC protocols on post-exercise 5 lower limb thermoregulatory, femoral artery and cutaneous blood flow responses. 6Methods: Ten males completed a continuous cycle exercise protocol at 70% maximal 7 oxygen uptake until a rectal temperature of 38°C was attained. Participants were then 8 exposed to lower-body CWI (8°C) for 10 min, or WBC (-110°C) for 2 min, in a 9 randomized cross-over design. Rectal and thigh skin, deep and superficial muscle 10 temperatures, thigh and calf skin blood flow (laser Doppler flowmetry), superficial 11 femoral artery blood flow (duplex ultrasound) and arterial blood pressure were 12 measured prior to, and for 40 min post, cooling interventions. Results: Greater 13 reductions in thigh skin (CWI, -5.9±1.8°C; WBC, 0.2±0.5°C; P < 0.001) and superficial 14 (CWI, -4.4±1.3°C; WBC, -1.8±1.1°C; P < 0.001) and deep (CWI, -2.9±0.8°C; WBC, -15 1.3±0.6°C; P < 0.001) muscle temperatures occurred immediately after CWI. 16Decreases in femoral artery conductance were greater after CWI (CWI, -84±11%; 17 WBC, -59±21%, P < 0.02) and thigh (CWI, -80±5%; WBC, -59±14%, P < 0.001) and 18 calf (CWI, -73±13%; WBC, -45±17%, P < 0.001) cutaneous vasoconstriction was 19 greater following CWI. Reductions in rectal temperature were similar between 20 conditions after cooling (CWI, -0.6±0.4°C; WBC, -0.6±0.3°C; P = 0.98). Conclusion: 21Greater reductions in blood flow and tissue temperature were observed after CWI in 22 comparison to WBC. These novel findings have practical and clinical implications for 23 the use of cooling in the recovery from exercise and injury. 24 25 3

This study determined the influence of cold (8°C) and cool (22°C) water immersion on lower limb and cutaneous blood flow following resistance exercise. Twelve males completed 4 sets of 10-repetition maximum squat exercise and were then immersed, semi-reclined, into 8°C or 22°C water for 10-min, or rested in a seated position (control) in a randomized order on different days. Rectal and thigh skin temperature, muscle temperature, thigh and calf skin blood flow and superficial femoral artery blood flow were measured before and after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). The colder water reduced thigh skin temperature and deep muscle temperature to the greatest extent (P < .001). Reductions in rectal temperature were similar (0.2-0.4°C) in all three trials (P = .69). Femoral artery conductance was similar after immersion in both cooling conditions, with both conditions significantly lower (55%) than the control post-immersion (P < .01). Similarly, there was greater thigh and calf cutaneous vasoconstriction (40-50%) after immersion in both cooling conditions, relative to the control (P < .01), with no difference between cooling conditions. These findings suggest that cold and cool water similarly reduce femoral artery and cutaneous blood flow responses but not muscle temperature following resistance exercise.

PurposeWe tested the hypothesis that both post-exercise and passive cold water immersion (CWI) increases PGC-1α and VEGF mRNA expression in human skeletal muscle.Method Study 1 Nine males completed an intermittent running protocol (8 × 3-min bouts at 90 % , interspersed with 3-min active recovery (1.5-min at 25 % and 1.5-min at 50 % ) before undergoing CWI (10 min at 8 °C) or seated rest (CONT) in a counterbalanced, randomised manner. Study 2 Ten males underwent an identical CWI protocol under passive conditions.Results Study 1 PGC-1α mRNA increased in CONT (~3.4-fold; P < 0.001) and CWI (~5.9-fold; P < 0.001) at 3 h post-exercise with a greater increase observed in CWI (P < 0.001). VEGFtotal mRNA increased after CWI only (~2.4-fold) compared with CONT (~1.1-fold) at 3 h post-exercise (P < 0.01). Study 2 Following CWI, PGC-1α mRNA expression was significantly increased ~1.3-fold (P = 0.001) and 1.4-fold (P = 0.0004) at 3 and 6 h, respectively. Similarly, VEGF165 mRNA was significantly increased in CWI ~1.9-fold (P = 0.03) and 2.2-fold (P = 0.009) at 3 and 6 h post-immersion.ConclusionsData confirm post-exercise CWI augments the acute exercise-induced expression of PGC-1α mRNA in human skeletal muscle compared to exercise per se. Additionally CWI per se mediates the activation of PGC-1α and VEGF mRNA expression in human skeletal muscle. Cold water may therefore enhance the adaptive response to acute exercise.

Using positron emission tomography, we report for the first time muscle perfusion heterogeneity in the quadriceps femoris in response to different degrees of cold-water immersion (CWI). Noxious CWI temperatures (8°C) increase perfusion in the deep quadriceps muscle, whereas superficial quadriceps muscle perfusion is reduced in cooler (15°C) water. Therefore, these data have important implications for the selection of CWI approaches used in the treatment of soft tissue injury, while also increasing our understanding of the potential mechanisms underpinning CWI.

Over the past decade, significant research has focussed on optimising the recovery of elite athletes. The premise behind such a theory is that sub-optimal recovery often leads to fatigue, reducing the quality of subsequent training sessions and/or competitive performances, whilst potentially hindering adaptive processes. There is now a plethora of research focussing on the impact of one such recovery strategy, cold-water immersion (CWI), and the benefits it may provide post-exercise.Proposed mechanisms of action are hypothesised to be a combined result of reduced perception of pain via decreased nerve conduction velocity alongside temperature and pressure induced changes in blood flow and reduced skeletal muscle temperature. As such, cold temperatures may facilitate enhanced recovery from exercise by reducing intramuscular temperature and metabolism, thereby limiting hypoxic stress and the generation of reactive oxygen species (ROS).

We assessed the effects of post‐exercise cold‐water immersion (CWI) in modulating PGC‐1α mRNA expression in response to exercise commenced with low muscle glycogen availability. In a randomized repeated‐measures design, nine recreationally active males completed an acute two‐legged high‐intensity cycling protocol (8 × 5 min at 82.5% peak power output) followed by 10 min of two‐legged post‐exercise CWI (8°C) or control conditions (CON). During each trial, one limb commenced exercise with low (LOW: <300 mmol·kg −1 dw) or very low (VLOW: <150 mmol·kg −1 dw) pre‐exercise glycogen concentration, achieved via completion of a one‐legged glycogen depletion protocol undertaken the evening prior. Exercise increased ( P < 0.05) PGC‐1α mRNA at 3 h post‐exercise. Very low muscle glycogen attenuated the increase in PGC‐1α mRNA expression compared with the LOW limbs in both the control (CON VLOW ~3.6‐fold vs. CON LOW ~5.6‐fold: P = 0.023, ES 1.22 Large) and CWI conditions (CWI VLOW ~2.4‐fold vs. CWI LOW ~8.0 fold: P = 0.019, ES 1.43 Large). Furthermore, PGC‐1α mRNA expression in the CWI‐LOW trial was not significantly different to the CON LOW limb ( P = 0.281, ES 0.67 Moderate). Data demonstrate that the previously reported effects of post‐exercise CWI on PGC‐1α mRNA expression (as regulated systemically via β‐adrenergic mediated cell signaling) are offset in those conditions in which local stressors (i.e., high‐intensity exercise and low muscle glycogen availability) have already sufficiently activated the AMPK‐PGC‐1α signaling axis. Additionally, data suggest that commencing exercise with very low muscle glycogen availability attenuates PGC‐1α signaling.

For centuries, cold temperatures have been used by humans for therapeutic, health and sporting recovery purposes. This application of cold for therapeutic purposes is regularly referred to as cryotherapy. Cryotherapies including ice, cold-water and cold air have been popularised by an ability to remove heat, reduce core and tissue temperatures, and alter blood flow in humans. The resulting downstream effects upon human physiologies providing benefits that include a reduced perception of pain, or analgesia, and an improved sensation of well-being. Ultimately, such benefits have been translated into therapies that may assist in improving post-exercise recovery, with further investigations assessing the role that cryotherapies can play in attenuating the ensuing post-exercise inflammatory response. Whilst considerable progress has been made in our understanding of the mechanistic changes associated with adopting cryotherapies, research focus tends to look towards the future rather than to the past. It has been suggested that this might be due to the notion of progress being defined as change over time from lower to higher states of knowledge. However, a historical perspective, studying a subject in light of its earliest phase and subsequent evolution, could help sharpen one’s vision of the present; helping to generate new research questions as well as look at old questions in new ways. Therefore, the aim of this brief historical perspective is to highlight the origins of the many arms of this popular recovery and treatment technique, whilst further assessing the changing face of cryotherapy. We conclude by discussing what lies ahead in the future for cold-application techniques.