The throwing elbow and shoulder of a baseball pitcher is subjected to high stress because of the repetitive nature and maximal force required for pitching (24,25,38,39). Baseball pitchers typically experience soreness and a loss of strength after pitching (12,26,33,39). The negative effects of repetitive overhand throwing may lead to decreases in performance and lead to potential overuse injuries and surgery. Olsen et al. (25) reported a 4-fold increase in arm surgeries for collegiate pitchers and a 6-fold increase in arm surgeries for high school pitchers over the 5-year period of 2000–2004. The increase in arm injuries could be the result of increases in games played per year and pitches thrown per year (21). Regardless of the cause, the increase in arm injuries brings to light the importance of strategies that improve recovery, delay fatigue, and reduce risk of injuries.
Traditionally, pitchers recover and minimize exertion between innings by resting in the dugout. Often, pitchers wear a jacket or place a towel on the throwing arm. The rationale for this practice is to keep the active muscles “loose” and warm. However, this recovery approach for pitchers is challenged by some more recent research on repetitive activities similar to pitching. Cooling, or “cryotherapy,” of the body or working muscles has been used primarily as a recovery agent but recent research precooling and intermittent cooling are showing positive signs for cryotherapy as an potential aid. Researchers have found positive results using cryotherapy on the overuse symptoms of pain, swelling, and inflammation (3,26). Cold therapy on the shoulder and legs has been shown to increase muscle fiber activation (27,28), help maintain repeated performance (35), and improve sprint performance (9).
Cryotherapy is also used to improve recovery (3,30,39). There are, however, conflicting results on the effect of local cooling of muscle on delayed-onset muscle soreness (10,14,16,22,30,32). The equivocal findings among cryotherapy studies are likely because of diverse research methods and cryotherapy application times.
Few empirical studies have examined the effects of cryotherapy on baseball-specific activity (12,24,37,39). Hannan et al. (15) found no significant differences in pitching variables after 20 minutes of preheating or precooling the arm. However, cold treatment has been shown to increase work (total repetitions) when applied intermittently (36,37). In one study, Verducci (37) performed intermittent cooling during baseball pitching and noted that although the exact nature of fatigue remains obscure, cryotherapy seemed to delay the onset of fatigue and increased throwing velocity of pitches without affecting accuracy. However, Verducci (37) tested pitching performance on flat ground instead of a pitcher's mound and did not objectively control for pitch count. Generally, baseball pitching performance is limited to a predetermined number of pitches. Not using a pitcher's mound or controlling pitch count makes it difficult to evaluate pitching performance in an ecologically valid manner.
A more recent study by Yanagisawa et al. (39) examined the effect of simulated-maximal pitching performance (98 pitches per trial) on recovery and shoulder strength using 5 different recovery methods. Yanagisawa et al. (39) found that cryotherapy combined with light shoulder exercise were the optimal methods for minimizing shoulder strength loss during shoulder abduction, internal/external rotation without shoulder abduction, and maximizing 24-hour subjective recovery.
Given the lack of ecological validity in the aforementioned study (37) and the fact that few empirical studies have been performed on baseball pitchers using intermittent cooling, the purpose of this study was to test the effect of a cryotherapy application on velocity, subjective exertion, and recovery time between innings during a simulated 5-inning game. The results and information derived from this study may be helpful for coaches, physical therapists, and athletic trainers with direct interaction with baseball players.
Experimental Approach to the Problem
Trained collegiate pitchers were asked to throw fastballs at a target at the rate of 1 pitch every 20 seconds (39). An inning consisted of 12 pitches with each participant given 6 minutes of rest between innings to replicate the time for the opposing pitcher warming-up and completing an inning (39).
There were 3 sessions. All sessions took place outdoors at the same time of day on a baseball field. The first trial for each participant familiarized the participant with the protocol, followed by 2 simulated game trials (Figure 1). Ambient temperature and relative humidity (RH) were recorded. During the rest period, 1 of the 2 randomly selected treatments (counterbalanced overall among participants) was administered to assess any difference between intermittent ice bag cooling of the shoulder and forearm (AC) and no treatment (NC) on pitching performance.
Participants were allowed to warm-up before pitching each inning to insure they were “loose” and to minimize risk of injury. The warm-up consisted of participants throwing for duration of their choice. After the first inning, warm-ups before all subsequent innings were standardized for each participant between trials. Warm-up pitches were not counted toward the overall total. The pitching protocol included a maximum of 60 pitches thrown (not including warm-up pitches) to simulate the first 5 innings of a baseball game. The 5-inning delineation is the minimum number of innings a pitcher must successfully complete to be granted a win in Major League Baseball.
There were 2 subjective scales used to determine perceived exertion and recovery. The Borg (6) 6–20 rating of perceived exertion (RPE) scale and 10–0 rating of perceived recovery scale (PRS) were used to assess subjective sensations associated with recovery and exertion during each trial. The Borg RPE scale is a subjective rating of effort being exerted during exercise (6). The Borg RPE scale is a 6–20 scalar representation of subjective intensity with 6 indicating no exertion and 20 indicating maximal exertion. The PRS is a subjective rating of recovery (19) that was used at the beginning, between innings and end of each session. The PRS is a 0–10 scalar representation of varying levels of an individual's perceived recovery status with 0 indicating no recovery and a 10 indicating full recovery. Each participant was familiarized with the RPE and PRS before testing. PRS recorded before the beginning of subsequent innings, with RPE was recorded at the end of each inning.
Eight trained amateur male baseball pitchers with no history of elbow or shoulder injury were recruited and participated in this study (n = 8, 21 ± 1 years; 180 ± 7 cm). All participants were competitively trained players, throwing 2 or more times per week for >20 minutes for a minimum of 6 weeks before the beginning of the study. The local Institutional Review Board approved the study and participants completed an informed consent form before participating. All participants indicated they were free of any health, arm, or shoulder issues that could affect the results of their performance. Participants refrained from heavy exercise, ingestion of caffeine, and ingestion of alcohol during the 24 hours preceding a trial. Participants dressed in baseball attire: cap, baseball pants, socks, baseball shoes, practice jersey or comparable cotton shirt and belt provided by the respective baseball organization of each participant.
Simulated Baseball Games
Participants underwent a simulated 1-inning familiarization to become accustomed to the pace between pitches and innings during each trial and to the complete testing protocol (Figure 1). Following the completion of the familiarization inning, a designated time was arranged for the participant to perform subsequent trials. Experimental trials began 24–48 hours after the familiarization session. Participants threw from a National Collegiate Athletic Association regulation pitcher's mound into a net that was placed directly behind home plate. A 5- to 7-day rest period separated the 2 experimental trials to simulate the accepted rest period between starts in baseball. Each experimental trial lasted approximately 1 hour.
During cooling treatment (AC), participants remained seated with 2 bags of wetted ice inside ice wraps (Mueller Sports Medicine, Inc, Prairie du Sac, WI, USA). The experimental treatment consisted of a bag of wetted ice positioned on the deltoid of the throwing arm and another positioned on the forearm. The control (NC) consisted of no treatment and the participant sitting in a chair. Participants were permitted to drink water ad libitum, although no participants chose to drink fluids. Each pitch was thrown into the same Rawlings Sports Training Net (Rawlings, St. Louis, MO, USA) and pitch velocity was evaluated using a radar gun (Bushnell Outdoor Products, Overland Park, KS, USA). Participants' average pitch speed for each inning and over all 5 innings of both treatment trials were recorded and analyzed. All testing sessions took place outside in a temperate environment (18.3 ± 2.8° C; 49 ± 4% RH; Figure 2).
Data were analyzed using SPSS version 20.0 (IBM SPSS Statistics, Somers, NY, USA), with results reported as means ± SDs. All p-values ≤ 0.05 were considered statistically significant. A 2-way (treatment × time) repeated measures analysis of variance (ANOVA) was used to test the primary dependent measure of pitch velocity. In the event of a significant interaction effect, paired samples t-tests were performed to determine differences in means between treatments at specific time points. A nonparametric Wilcoxon signed rank test for related samples was used to evaluate subjective ratings (RPE, PRS).
Nonparametric RPE and PRS data were totaled and placed into frequency distribution charts. Subjective measures of RPE and PRS were recategorized and their respective frequency distribution compared using a Wilcoxon signed rank test. RPE was then coded into 3 categories: 1 = light exertion (6–11, 32.5% of the responses), 2 = moderate exertion (12–14, 33.6% of the responses), and 3 = heavy exertion (15–20, 34.5% of the responses). PRS was then coded into 3 categories: 1 = fully recovered (10–8, 22.5% of the responses), 2 = moderately recovered (7–6, 40% of the responses), and 3 = not recovered (5–3, 37.5% of the responses).
The results of the ANOVA suggested that a significant interaction was found between treatments AC and NC (p = 0.04). Paired t-tests comparing pitch velocity by inning between the 2 treatments (Figure 3) resulted in significantly higher mean pitch speeds in the fourth inning (AC = 31.3 ± 2.01 m·s−1, NC = 30.0 ± 2.22 m·s−1, p < 0.01) and fifth inning AC treatment (AC = 31.3 ± 2.1 m·s−1, NC = 30.4 ± 1.99 m·s−1, p = 0.02) and significantly higher mean pitch speed across all innings with AC when compared with NC (31.2 ± 2 m·s−1 and 30.6 ± 2 m·s−1, respectively, p = 0.04, Table 1). Comparisons of AC and NC resulted in significantly lower RPE (p ≤ 0.01) and improved perceived recovery PRS (p ≤ 0.01) for AC when compared with NC.
This study examined the effect of 4-minute of intermittent cooling of the shoulder and forearm on pitching velocity and the subjective measures of recovery and exertion. Shoulder and forearm cooling between innings attenuated the decrease in pitching velocity when compared with NC, with a mean decrease of 2% in pitching velocity recorded during NC treatment. AC treatment significantly improved perceived recovery between innings. Comparison of treatments resulted in 35% reduction (p = 0.01) in perceived exertion. A comparison of pitch velocity by inning between the 2 treatments revealed significantly attenuated decreases in mean pitch speed (p = 0.04) in the fourth and fifth innings with AC treatment when compared with NC. The differences found in the first inning were found to be statistically different, although it should be noted that the participants were fully recovered before the start of each trial and were not fatigued before the beginning of each session. These data show that intermittent cryotherapy can attenuate velocity decreases in pitchers late in a baseball game, possibly resulting in improved performance. These findings support those of a previous study (37), which found that intermittent cooling attenuated decreases in pitching velocity and allowed for increased total work (26% more pitches).
It is well documented that the overhand throwing motion places tremendous stress upon the upper extremity and increases risk for overuse injuries (1,8,12,20,25,26). Fleisig et al. (12) reported peak torque placed on the throwing elbow reaches the maximum capacity of the ulnar-connective tissue. Szymanski (33) further expressed the potential for injuries related to the repetitive nature of baseball throwing, in particular, the large forces and torques essential to the overhand throw substantially stresses the shoulder during throwing. These stresses can lead to microtrauma in the soft tissues surrounding the elbow and, because of the repetitive nature of throwing, can result in overuse injuries from the accumulating damage.
Direct comparison of precooling research and pitching cryotherapy modalities share similar results when looking at the subjective exertion, subjective recovery, and pitch velocity. The precise mechanism in which cooling improves performance in comfortable and in hot environments is not fully understood. In a 2002 review article on the efficacy of precooling and performance, Marino (22) examined several strategies evaluating the effect of cryotherapy application and concluded that cold therapy attenuated decreased performance and improved recovery during repetitive exercise and heat stress.
Research has shown that proper application and duration of cryotherapy is activity specific. Because of the nature of the event or performance, certain applications may not be suitable for competition or recovery. Precooling has been shown to be effective before running and cycling (2,5,11,13,17,23,29,31,34), whereas interval cooling has been shown to help in repeated performance (36,37) and postbout strength and recovery (39).
Cold therapy is also shown to reduce the perceptions of exertion during exercise in the heat. Cryotherapy is reported to reduce the sensation of pain, inflammation, and the biomarkers associated with overuse (4,7). In our study, AC significantly attenuated a decrease in velocity over 5 innings of simulated play, resulting in significantly lower perceived exertion during baseball pitching. Subjective recovery was significantly improved during the AC treatment between innings when compared with NC. The effects of pain relief and diminished tissue temperature could explain the attenuated velocity and facilitated recovery with AC.
Limited research is published on cryotherapy and pitching performance, with various methods and populations being tested. In an earlier study on precooling and pitching, researchers administered 20 minutes of precooling as well as preheating in a temperate environment on nonelite pitchers (15). Results after 5 innings of pitching showed no significant differences in velocity or pitching performance between treatments. These findings could be attributed to the 20 minutes of precooling instead of an intermittent application during the trial.
Verducci (36) applied 3 minutes of intermittent cryotherapy protocol during repeated exercise performance. Verducci applied cooling to the shoulder and forearm between sets of pulls from a weight stack, resulted in significantly greater number of repetitions and total work performed (14.5% more pulls in the cryotherapy group).
In a second study, Verducci (37) applied 3 minutes of cooling to the shoulder and forearm of nonelite pitchers between innings. Pitchers were asked to report their subjective arm fatigue on a scale of 1–3: 1 = no fatigue, 2 = onset of fatigue, and 3 = arm is fatigued. A fatigue rating of 3 resulted in a termination of the pitching trial. Verducci (37) found that the cooling treatment increased the amount of work (22% more pitches) and velocity (1.9–4.9%) when compared with the control. However, participants of this study were not asked to perform on a pitching mound or outdoors, factors that could limit ecological validity and may support future research in this area.
A more recent study by Yanagisawa et al. (39) examined the effect of 5 different recovery protocols on maximal baseball pitching performance. Pitchers in this study were asked to throw 98 pitches, or the equivalent of a hypothetical maximal pitching effort. This study found that the cryotherapy alone and cryotherapy combined with light shoulder exercise were the superior methods to minimizing loss in shoulder strength and maximizing 24-hour subjective recovery. It is important to note that all treatments took place postbout and did not take place during the performance.
Findings by Verducci (36,37) combined with the present study suggests that intermittent cooling of the shoulder and forearm in between innings is a practical way to provide cold therapy in a baseball setting, supporting perceived recovery findings from previous studies and attenuated decreases in throwing velocity. With the improvements in perceived recovery, it is conceivable that an athlete may potentially improve performance later in a game. Improved subjective recovery coupled with the physiological effects of cryotherapy could be used to help reduce the occurrences of overuse injuries in athletes (4,5,7). However, although cryotherapy seems to help attenuate a decrease in pitching velocity and improve recovery, it is not clear how these variables will affect overuse injuries. With support from current research, the authors feel that pitcher injuries are a result of a complex set of variables and not directly caused by the number of pitches alone (18). Fatigue is associated with a decrease in proper technique, and the number of pitches thrown with poor form may in turn lead to an increased risk of injuries including those attributed to overuse.
Limitations of this study were that participants were tested in a temperate environment and were not asked to pitch to a hitter. The removal of hitters during this study was thought to limit the confounding effect of accuracy, thereby allowing for maximal exertion during each pitch. Pitch types were also controlled because of the universal nature of the fastball pitch and therefore a more broad inference of data results.
It is common and accepted that pitchers keep their arm “warm” between innings using various methods. The rationale behind this practice is to keep shoulder and forearm muscles warm between innings. However, pitchers are given ample time to stretch and warm-up before each inning. The pitcher's warm-up period is mandatory and helps promote blood flow to the muscles and consequently to the skin. The increase in blood flow to the surface of the body is a direct result of the increased metabolic heat produced from the working muscles and the subsequent response of the body to maintain thermal homeostasis. Conversely, surface cooling is shown to vasoconstrict blood vessels in the skin, eventually cooling the muscle temperature and attenuating rises in temperature because of excess metabolic heat. Anecdotally, all participants involved in the current study revealed they would choose intermittent cryotherapy as a treatment modality between innings. The authors feel it is important to note the environment was considered thermo-temperate environment, which was cool relative to many baseball games.
Baseball activity lends itself to repeated cryotherapy application because of the intermittent nature of the game. Cooling can take place between innings, providing an opportunity for application before and after activity. Ice therapy is a practical method of cryotherapy in an ecologically valid environment based on its availability, surface area contact, and constant temperature maintenance. Future studies should focus on repeated trials of intermittent cooling in simulated-game situations, controlling for different pitches and ambient temperature. These studies could focus on competitive collegiate and professional players for greater ecological validity.
The findings from this study suggest that intermittent cooling of the shoulder and forearm provided a positive effect on perceived recovery, perceived exertion, and pitching velocity during baseball pitching in a temperate environment. The mechanisms responsible for the ergogenic effect of cryotherapy on high-intensity intermittent activity remain to be determined. Cryotherapy treatment during a pitching performance seems to be a practical treatment when applied intermittently. Potential positive effects of cryotherapy include improved pitching performance by attenuating a decrease in pitch velocity, improved subjective recovery, and reduced subjective exertion.
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