Aerobic Capacity in Baseball Players

By Jose Vazquez, PT, RSCC and Gene Coleman, Ed. D., RSCC*E

Baseball is an anerobic sport that relies primarily on the ATP-PC system to provide energy for short bursts of high-intensity, explosive movements in game situations. Most movements in practice and game situations are over in 5 seconds or less. So, if the ATP-PC system is the dominant energy system in baseball, one might ask why is it important for players to have a sound aerobic base?


While it is true that running the bases, starting, stopping, changing directions, jumping, pitching, swinging, fielding and throwing all require energy in the form of adenosine triphosphate (ATP). There are actually three energy systems that provide the ATP needed to fuel these movements: 1) the phosphagen system (ATP-CP system); 2) anaerobic glycolysis; and 3) the oxidative system.  These three systems don’t work independently and are always active in every aspect of performance, some more than others. One system doesn’t turn on at a certain time and then switch off and allow another system to take over. All are available to “turn-on” at the onset of activity and they work simultaneously. One system is always the primary provider of ATP and the other two are lesser providers. Which one becomes the primary provider is determined by the duration and intensity of effort.

The ATP-PC uses the energy stored in the muscles (adenosine triphosphate and creatine phosphate) to provide an immediate source of energy for all-out effort lasting 6 to 10 seconds. It provides a lot of energy immediately, but for a short period of time. When the need for ATP exceeds the capacity of the ATP-CP system to provide it, anaerobic glycolysis takes over and becomes the primary source of energy for the next 60 to 120 seconds. The aerobic system kicks in when the effort decreases, e.g., between pitches, plays, bases and innings, practice sessions and games. It converts carbohydrates, fats and protein into ATP in the presence of oxygen. It is a much slower process making it ineffective for brief, all-out movements in game situations, but it can provide energy for sub-max effort for several hours.

So, if the aerobic energy system is not involved in most plays, why is important to have an aerobic base? One reason is recovery. The aerobic system is the primary energy system used during all forms of recovery. A sound aerobic base will help pitchers recover faster between pitches, innings and games, and help position players recover faster between swings, sprints, throws, fielding plays, innings and games.  The baseball year, regardless of whether you are a high school, college or professional player is a marathon. Professionals play 140 (minor league) to 162 (MLB) games in about 160-180 days. Highs school and college teams play a shorter season, but if a player participates in a high school or university’s spring program plus summer and fall leagues, the number of games can quickly approach 100 games. Players who engage in this type of year-around play and hope to make it through the season without burning out will need a sound aerobic base in order to recover.

Faster recovery can help delay fatigue and therefore allow a player perform better in the late innings of a game and weeks of the season. It can also improve skill development by helping players recover between reps and drills within and between practice sessions. Data also indicate that there is a relationship between aerobic fitness and heat stress. Players with a sound base tend to compete better with the heat stress of playing in the sun and become acclimated to the heat faster2.

Another benefit of having an aerobic base and performing some form of aerobic training involves the regulation of the autonomic nervous system. The autonomic nervous system (ANS) makes up one part of the body’s nervous system. The ANS is broken into two parts: the sympathetic (SNS) and parasympathetic (PNS) nervous systems. The SNS is the “fight or flight” system and is related to stress. The SNS kicks in when a player experiences emotional or physical stress, e.g. pitching or hitting in a tie game with two outs and the winning run in scoring position, executing a squeeze play, throwing a runner out at the plate, lifting heavy weights, running sprints, performing plyometrics, etc.  The SNS works overtime when players participate in high-intensity training and/or play in multiple games per week. Data suggest that being in a SNS-dominant state for prolonged periods of time can lead to burnout and overtraining.

The PNS is the “rest and digest” system. Because this is the state in which the body recovers most efficiently and absorbs and digests nutrients, its where athletes want to be when not competing or training. The PNS stimulates recovery and improvement occurs during recovery, not training. While HIT anaerobic activity stimulates the SNS, low-intensity aerobic methods stimulate the PNS. Data suggest that a having a sound aerobic can help the body recover from sympathetic stressors, achieve nervous system homeostasis, lower daily energy expenditure and prepare for future stresses that might come from training sessions and competitions3. ANS regulation is the basis Heart Rate Variability assessments.

Finally, there are data to suggest that aerobic fitness is related to in-game performance among MLB pitchers. A 2016 study by Gillett, et. al., observed that pitchers with an aerobic capacity greater than average had significantly better values on the metric measurements WHIP, (walks plus hits per inning pitched), strikeouts, K/BB (strikeout to walk ratio) and ERA1.


1.     Gillett JS, Dawes JJ, Spaniol FJ, et al. A Description and Comparison of Cardiorespiratory Fitness Measures in Relation to Pitching Performance Among Professional Baseball Pitchers. Sports (Basel). 2016;4(1):14. Published 2016 Feb 25. doi:10.3390/sports4010014.

2.     McLellan, TM. The importance of aerobic fitness in determining tolerance to compensable heat stress.

3.     Tian, K., et. al. The effect of aerobic and anaerobic endurance training on the regulating function of autonomic nervous system and its significance, 2006.


Jose Vazquez, PT, RSCC is the Head Strength and Conditioning Coach for the Texas Rangers. Gene Coleman was the Head S&C Coach for the Houston Astros from 1978-2012 and is currently a S&C consultant for the Texas Rangers, Professor Emeritus in the Exercise and Health Sciences Program at the University of Houston – Clear Lake and Website Education Manager



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