Don't Lose Your Cool With Cryotherapy: The Application of Phase Change Material for Prolonged Cooling in Athletic Recovery and Beyond

On Putting an End to the Backlash Against Electrophysical Agents

Electrophysical agents (EPAs) are core therapeutic interventions in academic physical therapy curricula around the world. They are used concomitantly with several other therapeutic interventions such as exercise, manual therapy techniques, medications, and surgery for the management of a wide variety of soft tissue disorders. Over the past decade, the practice of EPAs has been the subject of intense scrutiny in the U.S. This has been colored by some physical therapists publicly engaging in bashing rhetoric that has yet to be officially and publicly addressed by the guiding organizations which, together, regulate the practice of physical therapy in this country. Published in world renowned public media are unsubstantiated mocking remarks against the practice of EPAs and unethical allegations against its stakeholders. This rhetoric suggests that EPA interventions are "magical" treatments and that those practitioners who include them in their plans of care may be committing fraud. Such bashing rhetoric is in striking contradiction to the APTA's Guide to Physical Therapist Practice 4.0, which lists EPAs as one of its categories of interventions, the CAPTE's program accreditation policy, and the FSBPT's national licensing exam. The purpose of this commentary is to expose the extent of this discourse and to call to action the APTA, CAPTE, and FSBPT organizations, as well as physical therapists, with the aim at putting an end to this rhetoric.

Determination of the Effects of a Series of Ten Whole-Body Cryostimulation Sessions on Physiological Responses to Exercise and Skin Temperature Behavior following Exercise in Elite Athletes

The present study investigated the effects of a series of 10 whole-body cryostimulation (WBC) sessions (3 min; -110 °C) on physiological and thermal responses to a submaximal exercise test in 17 elite athletes. Participants performed an exercise test twice at similar levels of intensity before and after a series of ten WBC sessions. Before and during the test, each participant's oxygen uptake (VO2), heart rate (HR), internal temperature (Ti), and skin temperature in selected areas of the skin were measured, and the mean arterial pressure (MAP), physiological strain index (PSI), and mean skin temperature (Tsk) were calculated. The results show that during exercise, increases in Ti and the PSI were significantly lower after the WBC sessions, and although there were no significant changes in HR or the MAP, the Tsk was significantly higher. Following exercise, an increase in skin temperature asymmetry over the lower-body muscles was detected. A series of WBC sessions induced a tendency toward a decrease in temperature asymmetry over the thigh muscles. In conclusion, a series of ten WBC sessions does not induce significant modifications in physiological variables but does influence the PSI and Ti during exercise. Moreover, a series of ten WBC sessions influences the distribution of skin temperature and the magnitude of temperature asymmetries in the early phase of recovery.

Cool-Water Immersion Reduces Postexercise Quadriceps Femoris Muscle Perfusion More Than Cold-Water Immersion

PURPOSE

The muscle perfusion response to postexercise cold-water immersion (CWI) is not well understood. We examined the effects of graded postexercise CWI upon global and regional quadriceps femoris muscle perfusion using positron emission tomography and [15O]H2O.

METHODS

Using a matched-group design, 30 healthy men performed cycle ergometer exercise at 70% V̇O2peak to a core body temperature of 38°C, followed by either 10 min of CWI at 8°C, 22°C, or seated rest (control). Quadriceps muscle perfusion; thigh and calf cutaneous vascular conductance; intestinal, muscle, and local skin temperatures; thermal comfort; mean arterial pressure; and heart rate were assessed at preexercise, postexercise, and after CWI.

RESULTS

Global quadriceps perfusion was reduced beyond the predefined minimal clinically relevant threshold (0.75 mL per 100 g·min-1) in 22°C water versus control (difference (95% confidence interval (CI)), -2.5 (-3.9 to -1.1) mL per 100 g·min-1). Clinically relevant decreases in muscle perfusion were observed in the rectus femoris (-2.0 (-3.0 to -1.0) mL per 100 g·min-1) and vastus lateralis (-3.5 (-4.9 to -2.0) mL per 100 g·min-1) in 8°C water, and in the vastus lateralis (-3.3 (-4.8 to -1.9) mL per 100 g·min-1) in 22°C water versus control. The mean effects for vastus intermedius and vastus medialis perfusion were not clinically relevant. Clinically relevant decreases in thigh and calf cutaneous vascular conductance were observed in both cooling conditions.

CONCLUSIONS

The present findings revealed that less noxious CWI (22°C) promoted clinically relevant postexercise decreases in global quadriceps muscle perfusion, whereas noxious cooling (8°C) elicited no effect.

Cold for centuries: a brief history of cryotherapies to improve health, injury and post-exercise recovery

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.

Utilisation of performance markers to establish the effectiveness of cold-water immersion as a recovery modality in elite football

Optimal strategies for recovery following training and competition in elite athletes presents ongoing debate. The effects of cold-water immersion (CWI) compared to passive recovery (PR) though a triad of performance measures after fatiguing exercise within a normal micro-cycle, during mid-competitive training cycle, in elite male footballers were investigated. Twenty-four elite footballers (age 20.58 ± 2.55 years; height 179.9 ± 5.6 cm; weight 75.7 ± 7.5 kg; body fat 6.2 ± 1.7%) were randomly assigned to CWI or PR following a fatiguing training session. Objective measures included eccentric hamstring strength, isometric adductor strength, hamstring flexibility and skin surface temperature (T sk ). Subjective measures included overall wellbeing. Data were collected at match day+3, immediately post-training, immediately post-intervention and 24 hrs post-intervention. Physiological, biomechanical and psychological measures displayed significant main effects for timepoint for eccentric hamstring strength, T sk , overall wellbeing, sleep, fatigue, stress and group for eccentric hamstring strength, T sk and sleep (groups combined). Group responses identified significant effects for timepoint for CWI and PR, for eccentric hamstring strength peak force, sleep, fatigue, and muscle soreness for CWI. Significant differences were displayed for eccentric hamstring strength (immediately post-intervention and immediately post-training) for peak force and between CWI and PR eccentric hamstring strength immediately post-intervention. Linear regression for individual analysis demonstrated greater recovery in peak torque and force for CWI. CWI may be useful to ameliorate potential deficits in eccentric hamstring strength that optimise readiness to train/play in elite football settings. Multiple measures and individual analysis of recovery responses provides sports medicine and performance practitioners with direction on the application of modified approaches to recovery strategies, within mid-competitive season training cycles.

The cold truth: the role of cryotherapy in the treatment of injury and recovery from exercise

Cryotherapy is utilized as a physical intervention in the treatment of injury and exercise recovery. Traditionally, ice is used in the treatment of musculoskeletal injury while cold water immersion or whole-body cryotherapy is used for recovery from exercise. In humans, the primary benefit of traditional cryotherapy is reduced pain following injury or soreness following exercise. Cryotherapy-induced reductions in metabolism, inflammation, and tissue damage have been demonstrated in animal models of muscle injury; however, comparable evidence in humans is lacking. This absence is likely due to the inadequate duration of application of traditional cryotherapy modalities. Traditional cryotherapy application must be repeated to overcome this limitation. Recently, the novel application of cooling with 15 °C phase change material (PCM), has been administered for 3-6 h with success following exercise. Although evidence suggests that chronic use of cryotherapy during resistance training blunts the anabolic training effect, recovery using PCM does not compromise acute adaptation. Therefore, following exercise, cryotherapy is indicated when rapid recovery is required between exercise bouts, as opposed to after routine training. Ultimately, the effectiveness of cryotherapy as a recovery modality is dependent upon its ability to maintain a reduction in muscle temperature and on the timing of treatment with respect to when the injury occurred, or the exercise ceased. Therefore, to limit the proliferation of secondary tissue damage that occurs in the hours after an injury or a strenuous exercise bout, it is imperative that cryotherapy be applied in abundance within the first few hours of structural damage.