Accelerated Muscle Recovery in Baseball Pitchers Using Phase Change Material Cooling

Does High Medial Elbow Stress During Pitching Compromise the Dynamic Stabilizers of The Elbow?

Background

The flexor carpi ulnaris (FCU) and flexor digitorum superficialis (FDS) are thought to provide dynamic stability to the medial elbow, with a lesser contribution from the pronator teres (PT).

Hypothesis/Purpose

The purpose of this study was to determine if baseball pitchers with higher valgus elbow torque experience greater FCU and FDS strength loss.

Study Design

Controlled Laboratory Study.

Methods

A pilot study was performed to determine if middle and ring finger flexion strength tests preferentially activated the FCU and FDS versus the PT (10 men age 36±12 yr). EMG amplitudes, expressed as percent of maximal voluntary contraction (MVC) were compared between tests and muscles. In a field study of college baseball pitchers, middle finger, ring finger and grip strength were tested prior to, immediately after, and one day after 14 pitching performances in 10 pitchers (21±2 yr). Elbow valgus torque was measured from an inertial measurement unit, housed in a compression sleeve and pitchers were categorized as having high or low valgus torque.

Results

For the pilot study EMG activations were 74% FDS, 66% FCU and 35% PT for the middle finger test (muscle effect p=0.032) and 93% FCU, 61% FDS and 23% PT for the ring finger test (muscle effect p=0.005). In the field study, pitchers with high valgus torque showed marked post-game middle finger fatigue (88% of baseline) and incomplete recovery the following day (95%), while pitchers with low valgus torque showed no strength loss (107% post game, 106% a day later; group x time p=0.022). Results were similar for ring finger strength (high torque: 94% post game 96% a day later; low torque: 114% post game 107% a day later; group x time p=0.048). By contrast, grip strength was not different between pitchers with high versus low valgus torque (p=0.143).

Conclusion

High medial elbow stress during pitching fatigues the dynamic stabilizers of the medial elbow.

Level of Evidence

Level 3©The Author(s).

Phase-change material cooling blanket: A feasible cooling choice during transport after exercise-induced hyperthermia

BACKGROUND

Exercise-induced hyperthermia preceding the onset of exertional heatstroke requires a rapid reduction in the body core temperature (T_core) to ensure safety. In recent years, phase-change material (PCM) cooling devices have been increasingly used for rapid cooling after hyperthermia due to their superior capacity for heat absorption.

OBJECTIVES

This study aimed to evaluate the cooling performance and effectiveness of a PCM cooling blanket on heart rate (HR) and heart rate variability (HRV) recovery after exercise-induced hyperthermia.

DESIGN

Randomized cross-over.

METHODS

The study participants were 12 male volunteers who were engaged in professional training and completed an endurance exercise for approximately 30 min in a hot and humid environment (temperature ≈ 30 °C; relative humidity ≈ 66%). The participants underwent a 30-min cooling trial after exercise, receiving either treatment with a PCM cooling blanket (PCM group) or natural cooling (CON group). The T_core, HR, and HRV time-domain indices were used for analysis.

RESULTS

The T_core values were significantly lower in the PCM group during cooling. Reductions in the T_core from precooling to 20 min of cooling were significantly greater in the PCM group than in the CON group. The HR in the PCM group was lower than that recorded in the CON group at 10 and 20 min of cooling. The reduction in HR during cooling from precooling was also significantly greater in the PCM group. HRV time-domain indices during cooling in the PCM group were significantly lower compared with the CON group while elevations in some HRV time-domain indices from precooling to postcooling were significantly greater in the PCM group than in the CON group.

CONCLUSIONS

The PCM cooling blanket had good cooling performance and the ability to hasten recovery of both HR and HRV. It may serve as a feasible cooling choice during transport after exercise-induced hyperthermia.

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.

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.

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

Strenuous exercise can result in muscle damage in both recreational and elite athletes, and is accompanied by strength loss, and increases in soreness, oxidative stress, and inflammation. If the aforementioned signs and symptoms associated with exercise-induced muscle damage are excessive or unabated, the recovery process becomes prolonged and can result in performance decrements; consequently, there has been a great deal of research focussing on accelerating recovery following exercise. A popular recovery modality is cryotherapy which results in a reduction of tissue temperature by the withdrawal of heat from the body. Cryotherapy is advantageous because of its ability to reduce tissue temperature at the site of muscle damage. However, there are logistical limitations to traditional cryotherapy modalities, such as cold-water immersion or whole-body cryotherapy, because they are limited by the duration for which they can be administered in a single dose. Phase change material (PCM) at a temperature of 15°C can deliver a single dose of cooling for a prolonged duration in a practical, efficacious, and safe way; hence overcoming the limitations of traditional cryotherapy modalities. Recently, 15°C PCM has been locally administered following isolated eccentric exercise, a soccer match, and baseball pitching, for durations of 3-6 h with no adverse effects. These data showed that using 15°C PCM to prolong the duration of cooling successfully reduced strength loss and soreness following exercise. Extending the positive effects associated with cryotherapy by prolonging the duration of cooling can enhance recovery following exercise and give athletes a competitive advantage.