Table 5.

Characteristics of the experimental programs and the control groups.

Study	Training frequency (n/w)	Total of training sessions (n)	Experimental groups (description of the training process)	Control groups (description)
Brose et al. [30]	3	18	(Group 1) Wall Pulley: the overload training phase incorporated the use of a wall pulley device. This device was adapted by replacing the handle with a baseball. The overload tension applied amounted to 10 pounds, as precisely gauged by a calibrated spring scale. (Group 2) Weighted baseballs: the overload training regimen involved throwing baseballs that were weighted to 10 ounces (20 maximal throws). Given that the standard weight range for a baseball falls between 5.0 and 5.25 ounces, this adjustment effectively imposed nearly a twofold increase in load.	The control group was strictly prohibited from incorporating overload balls into their training regimen.
Carter et al. [36]	2	16	Plyometric training: In the experimental group, participants engaged in additional training exercises, with each exercise consisting of 3 sets and a variable number of repetitions ranging from 10 to 20, progressing gradually over the weeks. The exercises included: Latex tubing external rotation; Latex tubing 90/90 external rotation; Overhead soccer throw using a 6-lb medicine ball; 90/90 external rotation side-throw using a 2-lb medicine ball; Deceleration baseball throw using a 2–lb medicine ball; Baseball throw using a 2-lb medicine ball.	During the offseason, participants engaged in strength and conditioning activities, which encompassed regular cardiovascular conditioning and comprehensive overall strength training routines. These routines included isotonic exercises designed to strengthen the rotator cuff, and this regimen was consistent for both the control and experimental groups.
DeRenne et al. [31]	3	30	(Group 1) Overweight Balls: Players were introduced to baseballs weighing between 5 and 6 ounces. They completed a 50-pitch session. (Group 2) Underweight Balls: Players were introduced to baseballs weighing between 4 and 5 ounces. They completed a 50-pitch session.	Players consistently used 5-ounce baseballs and completed a 50-pitch session.
DeRenne et al. [34]	3	30	(Group 1) Combined Training: Participants in this group pitched using a combination of heavy, light, and standard balls, which weighed between 4 and 6 ounces. The total number of pitches per session ranged from 54 to 78. (Group 2) Blocked Training: In this group, participants initially trained with heavy and standard balls for the first five weeks, and in the subsequent five weeks, they trained with light and standard balls, all within the weight range of 4–6 ounces. The total number of pitches per session also varied from 54 to 78.	The control group consistently used 5-ounce balls for their throws, with the total number of pitches per session varying between 54 and 78.
Escamilla et al. [38]	3	12	Elastic tubing and distance-based interval throwing: The program involved the utilization of elastic tubing, specifically the “MVP Band” from A Change of Pace, Inc. in Davis, CA, USA. This component comprised 17 upper extremity resistance exercises intended to enhance muscular strength, power, and endurance. It is noteworthy that the MVP Band differs from the typical elastic tubing devices in that it is secured around the wrist rather than utilizing a handle held in the hands. Each of the 17 resistance exercises (e.g., focused on shoulder, and elbow) was executed for a single set, encompassing 20 to 25 repetitions. Furthermore, the subsequent 30-min segment entailed a distance-based interval throwing long-toss program.	The control group did not undergo any supplementary training program.
Escamilla et al. [35]	3	18	(Group 1) Throwers: Perform 8–12 repetitions for 36 sets. This program typically includes executing each repetition at a deliberate and controlled pace (at approximately 45–60°/s). It incorporates both concentric and eccentric muscle actions. (Group 2) Keiser Pneumatic: Aim for 8–12 repetitions over 32 sets. The resistance remains consistent throughout the entire range of motion and is unaffected by exercise speed. This program employs explosive training techniques, emphasizing baseball-specific functional training that engages the lower extremities, trunk, and upper extremities sequentially. (Group 3) Plyometric: Execute 6–10 repetitions across 32 different exercises. All exercises involve the stretch-shortening cycle, characterized by a rapid eccentric muscle action (prestretch), followed by a countermovement consisting of a rapid concentric muscle action to generate peak force as swiftly as possible. Medicine ball exercises engage the entire body, progressing from the lower extremities to the trunk and then to the upper extremities. These movements predominantly occur in transverse and diagonal planes, chosen for their relevance to throwing and similar baseball-related actions.	The control group did not undergo any supplementary training program.
Kurland et al. [39]	3	18	Circuit training: The training regimen comprised two circuits, each consisting of 10 stations. Each station involved a 20-s exercise period followed by a 40-s rest interval. These exercises were isokinetic in nature and included movements such as upright row, knee flexion/extension, elbow flexion/extension, hip flexion/extension, squats, and various others.	The control group did not undergo any supplementary training program.
Lachowetz et al. [53]	4	32	Strength training: Upper body strength training involved a total of 11 exercises, including movements such as shoulder rotation, shoulder abduction and adduction, shoulder extension, lateral row, and flat bench press. The weekly routine consisted of four training days, with six exercises performed on Monday and Thursday, and five exercises on Tuesday and Friday. Typically, each exercise was performed for three sets, with the last set supplemented by an additional 5 assisted repetitions after the initial 11 repetitions.	The control group did not undergo any supplementary training program.
Logan et al. [54]	5	30	(Group 1) Isotonic Resistance Training: In this group, players underwent isotonic resistance training using the Exer-genie device, which was designed to pull a baseball attached to an engine. Participants carried out 30 overhand throws daily. (Group 2) Throwing Training: This group engaged in 30 overhand throws using a standard baseball.	The control group was strictly prohibited from incorporating throwing or performing resistance training
Lust et al. [16]	3	18	(Group 1) Open Kinetic Chain/Closed Kinetic Chain Exercises: Open kinetic chain exercises encompassed both concentric and eccentric contractions and included four specific exercises in this study: Sitting scaption with the arm positioned at a 30° angle of horizontal abduction and internal rotation; Prone-lying horizontal abduction with the arm externally rotated; Prone-lying single-arm rowing; Supine-lying barbell bench press. Closed kinetic chain exercises featured in this group comprised the following: BAPS-board exercises; Step-ups; Balance exercises on an exercise ball. Plyometric exercises consisted of the following movements: 2-handed chest pass; 2-handed overhead soccer throw; 2-handed side throw; 1-handed baseball throw. (Group 2) Open Kinetic Chain/Closed Kinetic Chain/Core Stability: participants engaged in both open and closed kinetic chain exercises, similar to those described for Group 1. Additionally, a core stability program was introduced, featuring a progression of exercises: Dead bug exercises; Partial sit-ups; Bridging exercises; Prone exercises; Quadruped exercises; Wall slides; Ball exercises. The duration for all exercises within the core-strengthening program commenced at 30 s and progressed to intervals ranging from 1 min to 45 s	The control group was not required to attend any of the exercise training sessions.
McEvoy et al. [37]	3 every two weeks	15	Dynamic ballistic resistance training: In this training regimen, the group utilized the Plyometric Power System, a specialized device designed for dynamic weight training with adjustable loads. Players completed three sets of 6–8 maximal effort repetitions in exercises such as the bench throw and jump squat.	They exclusively took part in standard baseball training.
Newton et al. [40]	2	16	(Group 1) Medicine Ball Group: The exercises within this group included the explosive two-hand chest press and two-hand overhead throw, utilizing a 3 kg medicine ball. These exercises incorporated a countermovement. Participants completed 3 sets of 8 repetitions and progressed to four repetitions after completing the fourth week of training. (Group 2) Weight Training: In this regimen, participants engaged in the barbell chest press and barbell pullover exercises. During the initial four weeks, they completed 3 sets of 8–10 repetitions at maximum effort for each exercise. Afterward, the protocol transitioned to 6 to 8 maximum-repetition sets.	This group did not partake in any form of resistance training and solely followed the standard baseball training program identical to the experimental groups.
Potteiger et al. [55]	4	40	Weight and Sprint Training: This comprehensive hour-long workout combined strength and sprint training. It included 3 sets of 8–12 repetitions for each of the 8 exercises, such as bench press, military press, squat, lat pulldown, leg extension, leg curl, tricep extension, and bicep curl. The sprint portion of the workout involved a series of sprints, which comprised: A 10-s sprint at 50% of maximal effort; three 10-s sprints at 100% of maximum effort; one final 20-s sprint at 100% of maximum effort.	Dance Training: This dance training session lasted for 40 min and included a combination of aerobic dance routines and calisthenic activities, guided by a certified training instructor.
Reinold et al. [32]	3	18	Weighted Ball Training Program: In this program, throwing exercises were conducted from each position during every training session, using a set of five differently weighted balls (ranging from 2 to 32 ounces). The training positions included knee, rocker, and run and gun stances. Typically, two to three repetitions were performed per position per session, with the weekly total number of throws varying between 15 and 35.	The control group was strictly prohibited from incorporating underload or overload balls into their offseason training program for throwing.
Wooden et al. [56]	3	15	(Group 1) Individualized Dynamic Variable Resistance Mode: Participants engaged in exercises utilizing 100% of the variable resistance offered by the motor performance curve. Participants performed 6–7 sets of 10 maximal repetitions. (Group 2) Isokinetic Mode: In this mode, participants performed exercises at a constant velocity of 500°/s.	Not described.
Yang et al. [33]	3	18	Weighted Ball Training Program: In the weighted ball training program, three distinct throw positions were utilized (knee, rocker, run and gun), incorporating a range of five weighted balls (ranging from 2 to 32 ounces). The weekly volume of throws exhibited variability, spanning from 15 to 35 throws per week.	The control group was strictly prohibited from incorporating underload or overload balls into their offseason training regimen.

ND: not described.