Rebound Jumps Research Articles

Evaluation Of Stretch Shortening Cycle Performance Of Upper Limbs

PURPOSE: The purpose of this study was to suggest an indicator for the Rebound Jump-index (RJ-index) of upper limbs that reflects the Stretch-Shortening Cycle performance (SSC performance) of the upper limbs, and elucidate the inter-trial reliability and the criterion-related validity of this indicator. METHODS: The subjects were 31 male university track-and-field athletes between the ages of 18 and 21 years. Using an optical sensor, five rebound jumps with the upper limbs were performed on-site, and a jump height derived from the ground contact time and airborne time was calculated. The jump height was further divided by the ground contact time, and treated as the RJ-index of the upper limbs. For the rebound jumps, we instructed the subjects to keep their elbows as straight as possible during ground contact, keep the ground contract time short, and jump high. At the start of measurement, the hip joint angle was fixed to be 0°, and both upper limbs were kept perpendicular to the floor. In order to verify the reproducibility (inter-trial reliability) of the RJ-index measurement values of the upper limbs, we performed the same measurements 2 weeks later and derived the intraclass correlation coefficients (ICC) between the measurement values. In addition, To assess the criterion-related validity of the RJ-index of the upper limbs, we performed to the correlation between the RJ-index measurement and the shot put records. RESULTS: ICC (1,1) between the RJ-index measurement of upper limbs (0.19+0.07) and the re-measurement (0.18+0.08) was ρ=0.83, and ICC (1,2) was ρ=0.91. These values indicate that the measurement reproducibility was relatively high. Upon deriving the partial correlation coefficient assuming age and weight as control variables, a relatively high correlation was seen between the RJ-index of the upper limbs and the shot put records (r=0.59, p<0.01). CONCLUSIONS: Therefore, we think that it is apparent that the RJ-index of the upper limbs had a definite inter-trial reliability and this test may possibly have criterion-related validity as an assessment test for SCC performance of the upper limbs.

Importance of toe flexor strength in vertical jump performance

This study investigated whether toe flexor strength and foot arch height were related to force components during the ground contact phase in vertical jump performance. The toe flexor strength, foot arch height and vertical jump performance were studied in 31 healthy young men. For the measurement of toe flexor strength, participants explosively exerted maximum force on a toe grip dynamometer. The maximum isometric force (Fmax) and the rate of force development (RFD) of the toe flexor strength were evaluated. Foot arch height was assessed as the distance between the navicular tuberosity and the floor. Fmax and foot arch height were normalized by body mass (rFmax) and height, respectively. Three types of vertical jumps without arm swing were performed on a force plate: a squat jump (SJ), a countermovement jump (CMJ), and a rebound jump (RJ). Fmax, rFmax and RFD of the toe flexor strength were positively correlated with the vertical jump height in the SJ (r = 0.408, r = 0.452, r = 0.514) and CMJ (r = 0.377, r = 0.444, r = 0.548) and the rebound jump index in the RJ (r = 0.549, r = 0.582, r = 0.575); however, foot arch height was not correlated with the vertical jump performance, and it was only significantly correlated with the minimum ground reaction force relative to body weight during the unloading phase of the CMJ (r = -0.366). These results suggest that the toe flexor strength is an important parametre for enhancing the jump performance.

Effects of Plyometric Training on Sprint Running Performance in Boys Aged 9-12 Years.

Skilled sprinting is fundamental in many sports, especially to improve athletic performance in youth. This study therefore aimed to investigate the effect of plyometric training on sprint performance in boys aged 9–12 years. Twenty boys were divided into a plyometric training group (n = 9) and a control training group (n = 11). In both groups, participants performed respective training programs once per week for 8 weeks with measurements at baseline and post-intervention. Sprint performance was assessed by 50-m sprint time, sprint velocity, step frequency and step length at 10-m intervals. Jumping performance was assessed using horizontal, vertical and rebound jumps. The plyometric training group showed an improved sprint velocity at 20–30 m, 30–40 m and 40–50 m, and step length at 0–10 m, 20–30 m and 30–40 m (p < 0.05). Furthermore, only the plyometric group showed an increased standing long jump distance and rebound jump performance (p < 0.05). The control group did not show any significant changes in any variable. Our findings suggest that plyometric training in pre-adolescent boys improves sprint velocity and step length at the maximum velocity phase concomitant with increased horizontal and rebound jump performance.

Interday Reliability and Usefulness of a Reactive Strength Index Derived From 2 Maximal Rebound Jump Tests.

To examine the interday reliability and usefulness of a reactive strength index (RSI) derived from a maximal 5-rebound jump test (5max RJT) and a maximal 10-rebound jump test (10/5 RJT). Twenty male field-sport athletes (24.5 [3.0]y, 1.78 [0.1]m, 84.9 [5.2]kg) and 15 female participants (21.1 [0.9]y, 1.65 [0.73]m, 62.0 [5.1]kg) performed 2 maximal repetitions of the 5max RJT and the 10/5 RJT on 2 testing days after a specific warm-up. A 1-wk period separated testing days, and these sessions were preceded by a familiarization session. RSI was calculated by dividing jump height (in meters) by contact time (in seconds). The 5max RJT and the 10/5 RJT trial with the highest RSI on each testing day were used for reliability and usefulness analysis. Both tests were deemed reliable for determining RSI for male, female, and pooled male and female cohorts, as the intraclass correlation coefficients were ≥.80 and the coefficient of variation was ≤10%. Only the 5max RJT was rated as "good" at detecting the smallest worthwhile change in performance for female athletes (smallest worthwhile change: 0.10 > typical error: 0.07). The 5max RJT for men and the 10/5 RJT for men and women were rated "good" in detecting a moderate change in performance only. Both tests are reliable for the determination of RSI, but the usefulness of the tests in detecting the smallest worthwhile change is questionable.

Effect of Jump Direction on Joint Kinetics of Take-Off Legs in Double-Leg Rebound Jumps.

Vertical (VDJ) and horizontal (HDJ) double-leg rebound jumps are used as plyometric exercises in direction-specific training regimens for various sports. We investigated the effects of jump direction on joint kinetics of the take-off legs in double-leg rebound jumps. Twelve Japanese male track and field athletes performed VDJ, 100% HDJ, 50% HDJ (50% of 100% HDJ distance), and 75% HDJ (75% of 100% HDJ distance). Kinematic and kinetic data in the sagittal plane were calculated using a force platform and high-speed video camera. Hip negative power during the eccentric phase decreased from VDJ to 50% HDJ (VDJ, −4.40 ± 4.25 W/kg; 50% HDJ, −0.83 ± 2.10; 75% HDJ, −0.33 ± 0.83; 100% HDJ, 0 ± 0), while hip positive power increased from VDJ to 100% HDJ (VDJ, 4.19 ± 2.73 W/kg; 50% HDJ, 9.37 ± 2.89; 75% HDJ, 11.15 ± 3.91; 100% HDJ, 18.51 ± 9.83). Knee negative power increased from VDJ to 75% HDJ (VDJ, −14.48 ± 7.67 W/kg; 50% HDJ, −18.98 ± 7.13; 75% HDJ, −21.57 ± 8.54; 100% HDJ, −23.34 ± 12.13), while knee positive power decreased from VDJ to 75% HDJ (VDJ, 23.18 ± 9.01 W/kg; 50% HDJ, 18.83 ± 5.49; 75% HDJ, 18.10 ± 5.77; 100% HDJ, 16.27 ± 6.22). Ankle joint kinetics remained unchanged. Differences in hip and knee joint kinetics between VDJ and HDJ were associated with direction control, becoming more pronounced as jump distance increased.

Bone Mineral Density and Jumping Height in Pre-Menarcheal and Post-Menarcheal Physically Active Girls

Research background and hypothesis. Jumping ability correlates well with different bone values. The skeletal benefits of high-impact weight-bearing exercise have been shown to be greater when training is started prior to menarche. We hypothesized that significant differences would be apparent in the relationships between bone values and jumping height in favor of the girls’ prior menarche compared to post-menarcheal group. Research aim. The aim of the study was to investigate the relationships between jumping height and bone mineral density (BMD) in pre-menarcheal and post-menarcheal physically active girls. Research methods. In total, 113 adolescent girls from different competitive extramural athletic programs participated in this study. Femoral neck and lumbar spine BMD were measured. The heights of vertical jumps (i. e. countermovement jump (CMJ) and rebound jumps for 15 (RJ 15 s) and 30 (RJ 30 s) seconds) were obtained.Research results. After adjusting for major confounders (i. e. age, height, and body mass), the height of rebound jumps correlated only with femoral neck BMD and only in pre-menarcheal group (r = 0.37–0.46; p &lt; 0.05). No correlations were found between BMD variables and jumping height in post-menarcheal girls. The height of CMJ did not correlate with measured BMD variables in the studied groups.Discussion and conclusions. Early puberty is an opportune period to increase bone adaptation to mechanical loading due to the velocity of bone growth and endocrine changes at this time. We suggest that powerful repetitive vertical jumping may be more beneficial to bone health compared to single jumping activities in physically active girls prior to menarche rather than after it.Keywords: bone health, vertical jumps, puberty.

Variability of Plyometric and Ballistic Exercise Technique Maintains Jump Performance.

Chandler, PT, Greig, M, Comfort, P, and McMahon, JJ. Variability of plyometric and ballistic exercise technique maintains jump performance. J Strength Cond Res 32(6): 1571-1582, 2018-The aim of this study was to investigate changes in vertical jump technique over the course of a training session. Twelve plyometric and ballistic exercise-trained male athletes (age = 23.4 ± 4.6 years, body mass = 78.7 ± 18.8 kg, height = 177.1 ± 9.0 cm) performed 3 sets of 10 repetitions of drop jump (DJ), rebound jump (RJ) and squat jump (SJ). Each exercise was analyzed from touchdown to peak joint flexion and peak joint flexion to take-off. Squat jump was analyzed from peak joint flexion to take-off only. Jump height, flexion and extension time and range of motion, and instantaneous angles of the ankle, knee, and hip joints were measured. Separate 1-way repeated analyses of variance compared vertical jump technique across exercise sets and repetitions. Exercise set analysis found that SJ had lower results than DJ and RJ for the angle at peak joint flexion for the hip, knee, and ankle joints and take-off angle of the hip joint. Exercise repetition analysis found that the ankle joint had variable differences for the angle at take-off, flexion, and extension time for RJ. The knee joint had variable differences for flexion time for DJ and angle at take-off and touchdown for RJ. There was no difference in jump height. Variation in measured parameters across repetitions highlights variable technique across plyometric and ballistic exercises. This did not affect jump performance, but likely maintained jump performance by overcoming constraints (e.g., level of rate coding).

Difference between trampoline and rebound jumps during the down phase

Difference between trampoline and rebound jumps during the down phase

Ankle brace attenuates the medial-lateral ground reaction force during basketball rebound jump

ABSTRACT Introduction: The jump landing is the leading cause for ankle injuries in basketball. It has been shown that the use of ankle brace is effective to prevent these injuries by increasing the mechanical stability of the ankle at the initial contact of the foot with the ground. Objective: To investigate the effects of ankle brace on the ground reaction force (GRF) during the simulation of a basketball rebound jump. Method: Eleven young male basketball players randomly carried out a simulated basketball rebound jump under two conditions, with and without ankle brace (lace-up). Dynamic parameters of vertical GRF (take-off and landing vertical peaks, time to take-off and landing vertical peaks, take-off impulse peak, impulse at 50 milliseconds of landing, and jump height) and medial-lateral (take-off and landing medial-lateral peaks, and time to reach medial-lateral peaks at take-off and landing) were recorded by force platform during rebound jumps in each tested condition. The comparisons between the tested conditions were performed by paired t test (P&lt;0.05). Results: The use of ankle braces reduced the medial and lateral peaks of the GRF by -15.7% (P=0.035) and -24.9% (P=0.012), respectively, during the landing of the rebound jump. Additionally, wearing the brace did not affect any dynamic parameters of vertical GRF or temporal parameters of the medial-lateral GRF (P&gt;0.05). Conclusion: The use of ankle brace during basketball rebound jumps attenuates the magnitude of medial-lateral GRF on the landing phase, without changing the vertical GRF. This finding indicates that the use of brace increases the medial-lateral mechanical protection by decreasing the shear force exerted on the athlete’s body without change the application of propulsive forces in the take-off and the impact absorption quality in the landing during the basketball rebound jump.

Differences in take-off leg kinetics between horizontal and vertical single-leg rebound jumps

This study aimed to clarify the differences between the horizontal single-leg rebound jump (HJ) and vertical single-leg rebound jump (VJ) in terms of three-dimensional joint kinetics for the take-off leg, while focusing on frontal and transverse plane movements. Eleven male track and field athletes performed HJ and VJ. Kinematic and kinetic data were calculated using data recorded with a motion capture system and force platforms. The hip abduction torque, trunk lateral flexion torque (flexion for the swing-leg side), hip external and internal torque, trunk rotational torque, and the powers associated with these torques were larger when performing HJ because of resistance to the impact ground reaction force and because of pelvic and posture control. Pelvic rotation was noted in HJ, and this was controlled not only by the hip and trunk joint torque from the transverse plane but also by the hip abduction torque. Therefore, hip and trunk joint kinetics in the frontal and transverse plane play an important role in a single-leg jump, regardless of the jumping direction, and may also play a more important role in HJ than in VJ.

Reliability of accelerometry to assess impact loads of jumping and landing tasks

Overuse injuries, resulting from repetitive subacute impact loading, are a problem in high-performance sports. Monitoring of impact loading may aid in the prevention of these injuries. The current study aimed to establish the intra-day and inter-day reliability of a tri-axial accelerometer to assess impact loading during jumping and landing tasks. Twelve participants wore an accelerometer on their upper and lower back. They performed a continuous hopping task as well as drop landings and rebound jumps from three drop heights (37.5, 57.5 and 77.5 cm), peak resultant acceleration (PRA) was calculated for all tasks. The tasks were performed twice, one week apart at the same time of day. The difference in the mean, intra-class correlation coefficient, coefficient of variation and Cohen’s effect size were calculated as measures of reliability. PRA showed good intra-day reliability for the hopping task. Inter-day reliability of the PRA was moderate to good across all tasks. Reliability of PRA was slightly higher when accelerations were recorded on the lower back compared to the upper back. To assess impact loading, during continuous hopping, drop landings and rebound jumps, PRA recorded at both the upper and lower back appears to be a reliable measure.

Do accelerometers mounted on the back provide a good estimate of impact loads in jumping and landing tasks?

Artistic gymnasts are frequently exposed to both low- and high-magnitude loads through impacts with the apparatus. These impact loads are thought to be associated with the high injury rates observed in gymnastics. Due to the variable apparatus and surfaces in gymnastics, impact loads during training are difficult to quantify. This study aimed to use triaxial accelerometers mounted on the back to assess impact loading during jumping and landing tasks. Twelve participants were fitted with an accelerometer on their upper and lower back, before performing a continuous hopping task, as well as drop landings and rebound jumps from various heights (37.5, 57.5, and 77.5 cm) onto a force platform. Peak resultant acceleration (PRA) was low-pass filtered with four cut-off frequencies (8, 15, 20, and 50 Hz). Filtering of PRA with the 20 Hz cut-off frequency showed the highest correlations between ground reaction force (GRF) and PRA. PRA recorded at the upper back, filtered with a 20 Hz cut-off frequency, appears to provide a good estimate of impact loading for continuous hopping and rebound jumps, but less so for drop landings since correlations between GRF and PRA were only significant when landing from 57.5 cm.

Immediate Effects of Different Trunk Exercise Programs on Jump Performance.

The aim of this study was to investigate the immediate effects of trunk stabilization exercise (SE) and conventional trunk exercise (CE) programs on jump performance. 13 adolescent male soccer players performed 2 kinds of jump testing before and immediate after 3 experimental conditions: SE, CE, and non-exercise (NE). The SE program consisted of the elbow-toe, hand-knee, and back bridge, and the CE program consisted of the sit-up, sit-up with trunk rotation and back extension. Testing of a countermovement jump (CMJ) and rebound jump (RJ) were performed to assess jump performance. Jump height of the CMJ and RJ-index, contact time, and jump height of the RJ were analyzed. The RJ index was improved significantly only after SE (p=0.017). However, contact time and jump height did not improve significantly in the SE condition. Moreover, no significant interaction or main effects of time or group were observed in the CMJ. Consequently, this study showed the different immediate effect on the RJ between the SE and CE, and suggested the possibility that the SE used in this study is useful as a warm-up program to improve the explosive movements.

跳躍変数と下肢キネマティクスにおけるランニングシングルレッグジャンプとファンクショナルシングルレッグジャンプとの関係：脚間差に着目して

The present study aimed to clarify the relationships between running and functional single leg jumps in jumping variables and kinematics of the lower extremities in collegiate male basketball players, with specific emphasis on the differences between the two jumping legs. Twelve basketball players performed maximal single leg jumps with a running approach (RSJ) as well as functional jumps (FJs), including drop and bound jumps from a height of 30 cm (DJ), five repeated rebound jumps, vertical countermovement jumps, and squat jumps from a knee angle of 120° (SQJ) using the dominant leg (D-leg) and non-dominant leg (ND-leg). Three-dimensional kinematics data during each jump were collected using a 12 Raptor camera infrared motion analysis system (MAC 3D system) at a sampling frequency of 500 Hz. Jump height, jump index, running velocity, change in horizontal velocity at takeoff phase (ΔHV), reactive strength (%SQJ) and kinematics of the lower extremities were calculated. The symmetry indices of the jumping and kinematics variables were calculated as {2×(D-leg−ND-leg)/(D-leg+ND-leg)}×100. Jump heights, jump indices, and %SQJs in the RSJ and DJ, and ΔHV in the RSJ were significantly higher for the D-leg than for the ND-leg. During the takeoff phase in the two jumps, the joint angles and angular velocities of the ankle were significantly larger for the D-leg than for the ND-leg. Moreover, the symmetry indices of jump height in DJ, ΔHV in RSJ, %SQJ, and kinematics of the ankle joint in the RSJ and DJ were positively correlated with the symmetry index of jump height in the RSJ. These findings indicate that 1) the asymmetry of jump ability in the RSJ is attributable to the asymmetry of ankle behavior in the touchdown and takeoff phases, and 2) among FJs, the DJ may be useful for assessing and improving the asymmetry of the RSJ.

Sport-Specific Balance

This review includes the latest findings based on experimental studies addressing sport-specific balance, an area of research that has grown dramatically in recent years. The main objectives of this work were to investigate the postural sway response to different forms of exercise under laboratory and sport-specific conditions, to examine how this effect can vary with expertise, and to provide examples of the association of impaired balance with sport performance and/or increasing risk of injury. In doing so, sports where body balance is one of the limiting factors of performance were analyzed. While there are no significant differences in postural stability between athletes of different specializations and physically active individuals during standing in a standard upright position (e.g., bipedal stance), they have a better ability to maintain balance in specific conditions (e.g., while standing on a narrow area of support). Differences in magnitude of balance impairment after specific exercises (rebound jumps, repeated rotations, etc.) and mainly in speed of its readjustment to baseline are also observed. Besides some evidence on an association of greater postural sway with the increasing risk of injuries, there are many myths related to the negative influence of impaired balance on sport performance. Though this may be true for shooting or archery, findings have shown that in many other sports, highly skilled athletes are able to perform successfully in spite of increased postural sway. These findings may contribute to better understanding of the postural control system under various performance requirements. It may provide useful knowledge for designing training programs for specific sports.

The Effect of Caffeine on Maximal Oxygen Uptake and Vertical Jump Performance in Male Basketball Players

This study investigated whether performance enhancement from caffeine described by other researchers transfers to male basketball players. The effects of caffeine ingestion were studied in a maximal-effort test on a treadmill that was followed by a vertical-jump test. Five elite-level male basketball players completed a graded treadmill test that measured maximal oxygen uptake, blood lactate profiles, respiratory exchange ratio, and rating of perceived exertion at each 3-minute stage. After a 15-minute warm-down, the subjects performed 10 vertical rebound jumps. Each subject completed the test twice--once with a 3 mg·kg(-1) of body weight dose of caffeine and once with a placebo, with the dosage administered 60 minutes before commencement of exercise. The test was thus administered according to a double-blind protocol. No substantial trends were found between caffeine and control trials, regardless of trial order. The study showed that the specified dosage had negligible effects on the players' power and endurance performance and had no efficacy as an ergogenic aid for male basketball players.

The Effects of Self Myofascial Release on the Plantar Surface of the Foot During Sledge Rebound Jumps.

The Effects of Self Myofascial Release on the Plantar Surface of the Foot During Sledge Rebound Jumps.

An Investigation Into the Recovery Process of a Maximum Stretch-Shortening Cycle Fatigue Protocol on Drop and Rebound Jumps

The aim of this study was to investigate the recovery process of a maximal stretch-shortening cycle (SSC) fatigue workout on the biomechanical performance of drop jump (DJ) and rebound jump (RBJ) on a force sledge apparatus. Thirteen elite level rugby players performed sledge DJs and RBJs before and 15, 45, 120, and 300 seconds after a maximum SSC fatigue workout. Flight time, ground contact time (CT), peak force, reactive strength index (RSI), and leg-spring stiffness were the dependent variables. The DJ results showed that after 15 seconds recovery, there was a significant reduction in flight time (FT) (p < 0.01), RSI (p < 0.001), peak force (p < 0.01), and leg stiffness (p < 0.001). Similarly, the results for the RBJ indicated that the fatigue workout significantly reduced FT (p < 0.001), peak force (p < 0.01), RSI (p < 0.01), and significantly increased CT (p < 0.05) at the 15-second interval. The results also indicated a potentiation effect at the 300-second interval because of significant increases in RSI, peak force, and leg stiffness (p < 0.05) for the RBJ and significant increases in RSI (p < 0.05), peak force, and leg stiffness (p < 0.01) and a significant decrease in ground CT (p < 0.05) for the DJ. A maximal SSC fatigue workout had both an inhibiting and potentiating effect on DJ and RBJ performance depending on the recovery interval. The efficiency of the SSC function was reduced immediately after the cessation of the fatigue workout. A potentiation effect was evident for both jumps 300 seconds postfatigue.

各種パワー発揮能力からみた野球選手における投手と野手の体力特性：フィールドテストのデータをもとに

The purpose of this study was to investigate the characteristics of physical fitness in baseball pitchers and infielders focusing on variations in power output ability and stretch-shortening cycle (SSC) ability in field tests. Twenty-five male university pitchers and 22 university infielders participated. They performed five kinds of jumping (Standing triple jump (STJ), Standing double leg triple jump (SDTJ), Standing long jump (SLJ), Counter movement jump (CMJ), 5 rebound jumps (RJ)), and five kinds of medicine ball throw (Overhead throw (OT), Back throw (BT), Push of upper limb (Push), Shoulder horizontal adduction (SHA) and Twist of trunk throw (Twist)). Push, SHA and Twist were performed purely concentrically (concentric throw: CT) and with SSC movement (rebound throw: RT). These powers were assessed using the Throw index (Tauchi et al., 2006), and pre-stretch augmentations (Walshe et al., 1996) were calculated. It was found that: 1) OT, BT and SDTJ in pitchers were significantly higher than in infielders, and that there were significant correlations between pitched ball speed and OT, BT, and SDTJ. 2) Push RT-index and Push CT-index in infielders were significant higher than in pitchers, and significant correlations were found between thrown ball speed, batted ball speed and Push RT-index and Push CT-index in infielders. 3) SHA augmentation in infielders was significantly higher than in pitchers, and there was a significant correlation between thrown ball speed and SHA augmentation in infielders. 4) Twist of trunk power did not differ between pitchers and fielders. These results indicate that baseball pitchers and infielders obtain different physical fitness characteristics through the differences in their movement forms and required abilities.

The Acute Effects of Maximal Fatigue on the Subsequent Performance of Endurance Trained Athletes

Maximal stretch-shortening fatigue may have a detrimental effect on immediate performance of endurance-trained athletes, but once fatigue has subsided a potentiation effect may be evident. PURPOSE: The aim of this study was to investigate the acute effects of maximal stretch shortening cycle (SSC) fatigue on the subsequent performance of endurance trained athletes and to examine the pattern of recovery. METHODS: Nine endurance trained athletes performed four initial sets of drop and rebound jumps on sledge and force plate apparatus in order establish baseline levels of performance. A maximal SSC fatigue protocol was then performed by each subject; consisting of consecutive rebound jumps to a height of 90% of their maximum baseline jump until they could no longer reach their target on three consecutive jumps. This was followed immediately by one set of drop and rebound jumps at 15, 45, 120, 300 and 600 seconds post fatigue. Measurements of peak ground reaction force (GRF), ground contact time (CT), jump height, reactive strength index (RSI) and leg spring stiffness (kvert) were calculated for each drop jump (DJ) and rebound jump (RBJ). All recovery interval jumps were analysed and each subject's minimum and maximum post fatigue jump was selected for further analyses. A one-way ANOVA with repeated measures was used to evaluate the differences between the average of the baseline scores and the minimum and maximum scores achieved in the post tests. RESULTS: The fatigue protocol resulted in a significant reduction in jump height (p<0.001) and RSI (p<0.01) in the DJ and a significant reduction in GRF (p<0.01), jump height (p<0.01) and RSI (p<0.01) in the RBJ. The maximal fatigue workout also resulted in performance potentiation. During the latter recovery intervals, after fatigue had subsided, there was a significant improvement in performance in kvert (p<0.05) in the DJ and in GRF (p<0.001) and kvert (p<05) in the RBJ. This response was individual for each subject and occurred at either 300 or 600 seconds post fatigue. CONCLUSIONS: Exhausting SSC exercise induces a clear and immediate decrease in jumping performance and the biomechanical process of the jumps in endurance trained athletes. However, maximal SSC fatigue can also result in a potentiation affect in endurance athletes, in the latter stages of recovery. Funded by IRCSET