From 'Fix After Breaking' to 'Prevent Before Breaking'
NPB's approach to conditioning has fundamentally changed over the past 20 years. Before the 2000s, player injuries were accepted as unavoidable in NPB, with emphasis placed on post-injury rehabilitation. Even when pitchers suffered shoulder or elbow injuries, the prevailing belief was to heal while continuing to throw, resulting in many players continuing to play with chronic injuries. This 'fix after breaking' paradigm began to shift in the 2010s. The concept of PitchSmart (age-based pitch count guidelines) introduced in MLB spread to Japan, and the importance of pitch count management became recognized. Furthermore, the increasing number of NPB players undergoing Tommy John surgery (ulnar collateral ligament reconstruction) became a social issue, heightening interest in preventive medicine approaches. Currently, many teams have added sports medicine specialists to their staff and built systems for continuous monitoring of players' physical conditions. The recognition that detecting early signs of injury and adjusting training volume and playing opportunities to extend players' career longevity is rational from a team management perspective is gradually taking hold.
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Wearable Devices and the Practice of Workload Management
Playing a central role in conditioning science practice is workload management through wearable devices. In NPB, the number of teams having players wear GPS-equipped wearable devices during practice has increased since around 2018. This enables real-time measurement of players' movement distance, sprint counts, acceleration and deceleration frequency, and heart rate trends. For pitcher-specific devices, motion sensors worn on the elbow have attracted attention. These sensors quantify the load (torque) on the elbow for each pitch and issue alerts when cumulative load reaches dangerous levels. According to one team's trainer, the incidence of pitcher elbow injuries decreased by approximately 30% after introducing this device. An important concept in workload management is the Acute Chronic Workload Ratio (ACWR). This calculates the ratio between the past week's load (acute) and the four-week average load (chronic), with values exceeding 1.5 indicating sharply increased injury risk. Advanced NPB teams calculate this ACWR daily and adjust individual players' training loads accordingly. However, excessive application of workload management also carries the risk of insufficient conditioning, and optimizing load remains a challenging issue.
Mental Health and the Introduction of Performance Psychology
The most notable recent development in conditioning science is the focus on mental health. In traditional NPB, mental issues were often dismissed as lacking fighting spirit or mental weakness, with virtually no professional support systems in place. This situation began to change in the late 2010s when several active players publicly disclosed conditions such as depression and panic disorder. In response, the NPB organization established mental health guidelines in 2020 and recommended that each team employ specialists. Currently, more than 8 of the 12 teams employ sports psychologists or mental coaches on a full-time basis. The introduction of performance psychology is also advancing. Scientifically-based mental skills training is being provided, including pre-game routine construction, concentration maintenance under pressure, and methods for escaping slumps. Particularly noteworthy is the introduction of mindfulness meditation. Some teams implement mindfulness programs for the entire team, achieving results in player stress management and concentration improvement. Mental health initiatives are growing in importance not only for improving player performance but also from the perspective of supporting smooth transitions to second careers after retirement.
The Future of Integrated Conditioning - Intersection with Personalized Medicine
NPB's conditioning science is evolving toward integrated management of physical, technical, and mental aspects. At the forefront of this integrated approach is the introduction of personalized medicine concepts. Attempts have begun to design conditioning programs optimized for each individual by combining analysis of players' genetic characteristics, blood biomarkers, and gut microbiome. For example, some teams practice an approach of regularly measuring blood inflammatory marker concentrations and preemptively adjusting training volume for players showing upward trends, preventing injuries before they occur. Teams have also emerged that provide individualized nutrition programs including probiotic intake, focusing on the relationship between gut environment and immune function. However, such cutting-edge approaches face many challenges. These include ethical issues regarding genetic information handling, difficulty making decisions in areas where scientific evidence accumulation is insufficient, and above all, human resistance to treating players as collections of data. The ultimate goal of conditioning science is to create an environment where players can continue playing in physically and mentally healthy condition for extended periods, and technology must serve that goal.
Books on athlete mental health are also helpful references