The results of the moderator analysis are displayed in Tables 6 and 7. For both horizontally and vertically orientated outcome moderators, differences between subgroups were non-significant with low to moderate heterogeneity. For horizontally orientated outcomes, the effect size for programme duration, as measured by number of weeks, was larger for those studies longer than 7 weeks (0.96 [− 0.15, 2.08]) than it was for those shorter than 7 weeks (0.43 [− 0.00, 0.86]) and favoured HPT in both cases. For vertically orientated outcomes, there was little difference between longer (> 8 weeks; − 0.19 [− 0.83, 0.46]) and shorter programmes (≤ 8 weeks; 0.08 [− 0.28, 0.44]. For horizontally orientated outcomes, there was a large effect size (1.91 [0.87, 2.96]) for programmes that had more than twelve sessions, with only a small effect size (0.30 [− 0.06, 0.66]) in those that had fewer than twelve. Again, this favoured HPT in both cases. The trend was not apparent for

If this is the case, a transition by coaches to more horizontally orientated exercises and outcome measures is warranted, though not at the complete expense of vertically orientated.

The researchers, examining the horizontal and vertical positioning of the centre of mass during take-off, demonstrated different positions of the body’s centre of mass in both horizontal and vertical jumps. Vertical jumps showed practically no displacement of the centre of mass in a horizontal direction at take-off. However, the difference in the vertical displacement of the centre of mass was comparable between both types of jump. This implies that there is a horizontal and a vertical component to horizontal jumps, whereas vertical jumps possess a vertical component only. Cappa and Behm

Recently, there has been an increased interest in fine-tuning the specificity of training stimuli to meet the demands posed within sport. For example, it has been argued that force production in a horizontal direction is vital in underpinning acceleration capacity in athletes with horizontally orientated weighted sled pushing thought to be an appropriate method for training this physical capacity [35]. This interest has been generated by research which has highlighted the shortcomings of vertically orientated exercise for the enhancement of horizontally orientated movement.

ccordingly, the principle of training specificity informs the type of training stimuli that a coach chooses for an athlete to optimise performance. In this way, a horizontal jump might be more effective than a vertical jump in eliciting increases in sprint speed; whereas, a vertical jump may be more beneficial for a sports skill such as a rebound jump in basketball.

A 3D motion analysis system with six cameras (Qualisys System, Qualisys AB, Gothenburg,Sweden) was used to record the kinematic and kinetic parameters of the lower limb during single-legdrop landing. Two force plates (Advanced Mechanical Technology, Inc., Watertown, MA, USA) wereused to measure the ground reaction forces (GRFs) and determine the pressure centers during landing.Twenty-eight markers (super-spherical markers, Qualisys AB, Gothenburg, Sweden) were attached tospecific anatomical landmarks of the lower limbs, as described by Helen Hayes [20 ]. Cameras were setat 100 frames/s with a shutter speed of 1/500 s. The cutoff frequency used to reduce noise was set at6 Hz. Two force plates were connected to a sync LED for image analysis and synchronization, and aQualisys A/D board was used for time synchronization. The landing force were collected at 400 Hz.All subjects performed single-leg drop landings from a 45-cm-high box; the distance between thebox and force plate was set at 20 cm [21 ]. Subjects wore short stretch pants and were instructed to foldtheir arms over their chests to limit upper limb movement.

Taekwondo demonstrations always require high-intensitytasks, such as jump landing, kicking, breaking, and turning kicks [ 1, 2 ], which require agility, speed,flexibility, strength, and endurance [1 ,3,4 ]. Injuries in Taekwondo demonstration athletes commonlyinvolve the lower limbs [1] and usually occur during jump landing [5].Depending on the jump-landing height, at least 10 times body weight is applied to the ankles,which creates excessive shock at the joints

Both of the present experimental groups (CSG and PG) significantly improved their SJ height relative to the CG ( Table 6), with only slight differences between CSG and PG. For PG, the increase can be explained by the training specificity principle, with a similarity in kinetics and kinematics between jump and half-squat exercises. By contrast, the CSG increased their SJ height relative to the PG and CG, with no significant difference between the latter 2 groups. In young untrained men, Vissing et al. ( 41) observed a significant improvement in CMJ in both of their experimental groups (plyometric and conventional resistance training). On average, 24% 1RM improvements during squats resulted in CMJ and SJ increases of approximately 6.8% (

The improvement in jump smash and static squat jump performance under the EMS + strength condition is consistent with previous research demonstrating the benefits of electrical stimulation for enhancing muscle strength and explosiveness. The jump smash involves a high degree of lower limb explosiveness and coordination with upper body actions, making it a demanding movement for athletes [28]. Similarly, the static squat jump requires substantial force production, particularly in the lower limbs. The significant improvements observed in both of these exercises in the EMS + strength condition can be attributed to the enhanced recruitment of fast-twitch muscle fibers facilitated by the electrical pulses

These findings suggest that plyometric training positively affects horizontal jump performance,albeit with improvements lower than those recorded for vertical jump performance (9% to 28%, asobserved previously). One possible explanation for the weaker effect of plyometrics on horizontaljump performance in comparison to vertical jump performance is the specificity of the plyometrictraining and the optimization of the force vector and muscle stimulation during the exercises

Radu, Făgăra¸s [45] Women 16 to 17 yo 15 Case reports; 10-weekperiod interventionTwo plyometric sessions per week. The followingexercises were included in the program: double legand single-leg jumps; squat jumps; crossoverjumps; increase and decrease jumps; broad jumps;box hop jumps; scissors jumps; single legbounding; and power skipping.Players meaningfully improved theiroverall performance at flight time, contacttime, height, and power during the 15-sand 30-s jumping tests. No meaningfulchanges were found in stiffness.Gjinovci, Idrizovic [48] Women 21.9 yo 41Randomizedcontrolled trial;12-week periodinterventionTwo experimental groups: plyometric andskill-based. Each group had two sessions per week.Plyometric training included lower-body exercises(leg hops, vertical jumps, tuck jumps,lateral/diagonal jumps, broad jumps, obstaclejumps, box jumps, and drop jumps) and upperbody exercises (throwing exercises). The total ofsets/week varied between 12 and 24 depending onthe body part, and the repetitions between 40 and58/week. Skill-based training consisted ofvolleyball drills, small-sided games, andgame drills.Both groups showed meaningfulimprovements in counter-movementjump performance. The plyometric grouphad an improvement of 27.6%, and theskill-based group had an improvement of18%. Plyometric training was largelybetter than skill-based trainingconsidering the effects oncounter-movement jump performance.Hewett, Stroupe [44] Women 15 yo 20 Case reports; 6-weekperiod interventionExperimental group had three sessions per week.The program followed three phases: Techniquephase (2 first weeks), fundamentals phase (using aproper technique to build strength and power) andperformance phase (focusing on achievingmaximal jumping).The plyometric group meaningfullyimproved vertical jump performance by9.2%. Decreases in peak landing forceswere observed.Hrženjak, Trajkovi´c [47] WomenYouth and juniorplyometric group:16.18 yo.Control group: 16.3 yo.N = 60Plyometricgroup(n = 31);controlgroup(n = 29)Randomizedcontrolled trial; 6-week periodintervention6 weeks; five training sessions per week (90 to 120min). The number of training sessions was 15.The set model for development of explosive legpower consisted of five exercises, and exerciseswere done in the first part of the training session,after a 30-min warm-up.Both the plyometric and the control groupshowed significant improvements (p <0.05) in joint kinematics from pre- topost-training on most of the measures forlinear velocity, except for the linearvelocity in the hips during the eccentricphase (p = 0.669 for the plyometric group,p = 0.595 for the control group), wherenone of the group showed significantimprovement.

The available evidence suggests that PLY, either alone or in combination with other typical training modalities such as WT, elicits numerous positive changes in neural and musculoskeletal systems, muscle function and athletic performance of healthy individuals. Specifically, the reviewed studies have shown that long-term (6-24 months) PLY represents an effective training method for enhancing bone mass in pre-pubertal/early pubertal children, young women and pre-menopausal women. Furthermore, short-term (6-15 weeks) PLY can change the stiffness of various elastic components of the muscle-tendon complex of plantar flexors in both athletes and non-athletes; however, due to conflicting results in the literature, it is difficult to arrive at a definitive conclusion on this issue.