WHAT HAPPENS IN A GAME: CLINICAL RESEARCH
An interesting study was performed by Potteiger, et al  in which they measured several physiological and bio-chemical responses experienced by pitchers during the course of pitching a game. Six college-age men with varsity pitching experience at the collegiate level participated in the study. They pitched a simulated game of seven innings, with 14 pitches per inning. The subjects were given a six minute rest period before beginning their next inning, and were encouraged to exert their normal level of effort with each pitch. The following indices were measured, pre and post performance:
1) Heart rate.
2) Blood lactate (a by-product of lactic acid).*
3) Serum glucose.
4) Free fatty acids.
5) Oxygen consumption (VO2).*
In addition, 24 hours later, serum creatine kinase (CK)* and lactate dehydrogenase (LDH)* were analyzed as an indicator of skeletal muscle damage. For our purposes in this report, the items marked with the (*) are the ones I want to discuss further.
1) Lactic acid levels were unchanged between pre-exercise values and post game measurements.
2) VO2 was equal to 45% of maximum.
3) A significant difference for both CK and LDH existed between the pre-exercise and 24 hours-post-exercise values.
1) Lactic acid levels did not change through the course of the game from their pre-game values. This makes sense, because pitching is not the type of activity that generates lactic acid. The burning feeling one gets in the muscles during intense weight lifting or sprinting is never felt by a pitcher.
In fact, Vern Gambetta, Director of Athletic Development for the New York Mets and former Director of Conditioning for the Chicago White Sox refers to baseball as an "alactic-anaerbobic" activity, meaning that no lactic acid is produced. At a minimum, any lactic acid that may be produced during the act of pitching is easily cleared by the body, so its production is not a limiting factor in pitching performance.
The phosphagen energy system provides energy for sports activities that last several seconds and is involved in all forms of exercise regardless of intensity . This includes baseball and softball pitching. Phosphagen replenishment occurs within 20 to 30 seconds. This means that after 20 seconds of rest following a pitch, the main energy system used for pitching is re-charged and ready to go again. This allows for the many and repeated pitches thrown by baseball and softball pitchers.
2) VO2, expressed as a percentage of maximum uptake, means that the pitchers were working at a level equal to 45% of their capacity - not very high. According to the authors, it is believed that this level of oxygen uptake during the work period (pitching) is for the purpose of resynthesizing ATP and PC (phosphagen) stores.
What this means in a practical sense is that oxidative (aerobic) activities contribute little to conditioning for the act of pitching. Excessive aerobic training, such as long, slow distance (LSD) running or lots of time on an exercise bike will allow a pitcher to perform at an even lower percentage of VO2 max. This will help the pitcher who decides to enter a 10K or marathon, but will do nothing for their pitching performance. Aerobic capacity is certainly not a limiting factor in pitching performance.
Aerobic training can be useful as the foundation of a ballplayer's conditioning regimen, but spending more than 10-15 minutes, 2-3 days/week for this purpose is a waste of valuable training time. One exception to this rule would be after an extended pitching appearance. An easy run of about 15 minutes duration can help in recovery, getting the blood flowing to deliver needed nutrients to the damaged muscles and tendons that have been strenuously exerted, as well as helping to "wash out" any waste metabolites generated during this physical activity.
Long slow distance running is also a very poor way of developing leg strength, something that is valuable for a pitcher to have. The act of pitching occurs in a very short timeframe, not continuous and long lasting as occurs with LSD running. Pitching is more analogous to a single rep of a plyometric exercise using the legs. Consider the muscular development and strength of the legs of marathon runners versus 100 meter sprinters. Baseball & softball players are aiming for something in between these two extremes. Finally, LSD training can detract from strength and power development, so keep this activity to a minimum as discussed above.
3) CK and LDH values were significantly elevated 24 hours after exercise. According to other investigators, this may be an indicator of skeletal muscle damage. In fact, LDH levels in the blood are used to make a diagnosis of heart attack, which is damaged heart muscle. Eccentric muscle contractions (muscle contraction while the muscle is lengthening) that commonly occur during pitching cause greater mechanical stress leading to an increased release of CK and LDH enzymes into the blood.
Eccentric contractions occur during pitching in two main muscle groups: A) The muscles of the legs contract eccentrically after pushing off the pitching rubber and completing the stride. B) The muscles of the arm contract eccentrically (particularly the shoulder - external rotators) during the deceleration (after ball release) phase of the pitch.
The pitchers in this study each threw 98 pitches, a not excessive number. Yet this workload was rigorous enough to elicit elevated readings of indicators of muscle damage. Clearly some rest is warranted between extended pitching appearances. Continuing to work at maximum or near-maximum intensity not only puts the body into a catabolic state, it also does not allow time for rest and proper nutrition to make their contributions to the recovery process. The body actually develops and adapts to the stimulus of a hard workout (like pitching) during the REST period between bouts of strenuous activity.