Influence of jumping strategy on kinetic and kinematic variables (original) (raw)
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Kinematic and Neuromuscular Measures of Intensity During Plyometric Jumps
Journal of Strength and Conditioning Research, 2017
The aim of this study was to assess jumping performance and neuromuscular activity in lower limb muscles after drop jumps (DJ) from different drop heights (intensity) and during continuous jumping (fatigue), using markers such as reactive strength, jump height, mechanical power and surface electromyography (sEMG). The eccentric (EC) and concentric (CON) sEMG from the medial gastrocnemius (MG), biceps femoris (BF) and rectus (R) muscles were assessed during all tests. In a cross-sectional, randomized study, eleven volleyball players (age 24.4±3.2 years) completed 20 to 90cm (DJ20 to DJ90) drop jumps and a 60-s continuous jump test. A one-way ANOVA test was used for comparisons, with Sidak post-hoc. The α level was <0.05. Reactive strength was greater for DJ40 compared to DJ90 (p<0.05; ES: 1.27). Additionally jump height was greater for DJ40 and DJ60 compared to DJ20 (p<0.05; ES: 1.26 and 1.27, respectively). No clear pattern of neuromuscular activity appeared during DJ20 to DJ90: some muscles showed greater, lower, or no change with increasing heights for both agonist and antagonist muscles, as well as for eccentric and concentric activity. Mechanical power, but not reactive strength, was reduced in the 60-s jump test (p<0.05; ES: 3.46). No changes were observed in sEMG for any muscle during the eccentric phase nor for the R muscle during the concentric phase of the 60-s jump test. However, for both MG and BF, concentric sEMG was reduced during the 60-s jump test (p<0.05; ES: 5.10 and 4.61, respectively). In conclusion, jumping performance and neuromuscular markers are sensitive to DJ height (intensity), although not in a clear dose-response fashion. In addition, markers such as mechanical power and sEMG are especially sensitive to the effects of continuous jumping (fatigue). Therefore, increasing the drop height during DJ does not ensure a greater training intensity and a combination of different drop heights may be required to elicit adaptations.
Scientific Reports, 2023
Athletic women have shown a higher risk of ACL injury during jump landing compared to men. Plyometric training can be an alternative way to minimize the risk of knee injuries via the changed muscle activity patterns. Hence, the aim of this study was to determine the effects of a 4-week plyometric training program on the muscle activity pattern in different phases of one-leg drop jump in active girls. Active girls were randomly allocated into 2 groups (Plyometric training = 10, Control group = 10) where the plyometric training group (PTG) performed 60 min exercises, 2 sessions/1 week for 4 weeks while the control group (CG) had their daily activity. In the pre to post test, the sEMG was recorded from the Rectus Femoris (RF), Biceps Femoris (BF), Medial Gastrocnemius (GaM), and Tibialis Anterior (TA) muscles of the dominant leg during the Preparatory phase (PP), Contact Phase (CP), Flight Phase (FP) of one-leg drop jump. Electromyography variables (Signal amplitude, Maximum activity, Time to peak (TTP), Onset and activity time and Order muscle activity) and Ergo jump variables (Time of preparatory phase (TPP), Time of contact phase (TCP), Time of flight (jump height) phase (TFP), and Explosive power were analyzed. The Univariate ANCOVA test showed a significant difference between the two groups in Activity Time, whilst adjusting for pre-test as a Covariate, only in TA muscle (F (1,17) = 5.09, p = 0.038, η 2 = 0.230). In PTG. TA (− 15%), GaM (− 19%), and BF muscles (− 9%) started their activity earlier while there was no significant difference between the two groups at the Onset time. TTP of RF was significantly different between the 2 groups only in the PR phase (0.216 ± 0.07 vs 0.153 ± 0.09 s) (p = 0.049, 95% CI = 0.001, 0.127). Results of the present study suggest that a 4-week plyometric training can improve the stability of leg joints via earlier recruitment of muscles and change activity patterns in lower limb muscles. It also recommends that the preparatory phase before landing be considered an important stage in preventing sports injuries in a training program. Plyometric training is generally expected to enhance performances during stretch-shortening cycle (SSC) exercises. Among the mechanisms of plyometric training, it is possible to mention the potential of the electric currents of the muscle (neural adaptations), biochemical-mechanical potential, and restoring the elastic energy of the muscles 1,2. Plyometric training causes modulation in the action of deep muscle receptors. Studies have shown that the muscle spindle participates in power output through a stretch reflex mechanism in plyometric training 3. By contrast, another proprioceptor, Golgi tendon organs (GTOs), located in tendons, mainly prevents muscle over-contraction 3 , which reduces the sensitivity of this organ to plyometric training 4 , which increases the recruitment of motor units and changes the pattern of muscle activity during jumping 5,6. Therefore, plyometric
Pedagogy of Physical Culture and Sports
Background and Study Aim. Athletic jumps are specific cyclically-acyclic movements that despite the good performance of the techniques require from competitors a high level of motor, specific-motor and functional abilities. The aim of this study was to examine the response effect of vertical and horizontal plyometric training on explosive capacity and kinetic variables in long jump athletes. Material and Methods. The participants of this study were twenty professional jumpers (22.5 ± 4.2 years; 178.4 ± 9.8 cm; 70.3 ± 7.6 kg) who were divided into two groups: experimental (plyometric training) and control (standard training). They participated in the last track and field championship in country, moreover, three of them participated in the last Asian games, and one athlete participated in the world track and field championship. The experiments were conducted on June-July 2019 in twenty professional athletes. All tests were performed after a standard warm up protocol. The place of came...
The effect of plyometric training volume on jumping performance
This study compared high and low daily volume periodized plyometric training programs and their effect on countermovement jump (CMJ) performance over a 2 week testing time course after training. Thirty-five male subjects participated. Subjects CMJ was tested on a force platform prior to and at 2, 6, 10 and 14 days post training. Peak vertical ground reaction force (GRF), reactive strength index-modified (RSI mod), jump height (JH), and body mass were assessed. No differences were found between the high and low volume training groups. Subjects GRF, RSI mod, and JH performance was improved in a range of 6 to 14 days post-training. Low and high volume periodized plyometric training programs produced equal results. Six to 14 days of recovery post training was required to accrue the training benefit.
Journal of Strength and Conditioning Research, 2010
Arabatzi, F, Kellis, E, and Saè z-Saez de Villarreal, E. Vertical jump biomechanics after plyometric, weight lifting, and combined (weight lifting + plyometric) training. J Strength Cond Res 24(9): 2440-2448, 2010-The purpose of this study was to compare the effects of an Olympic weight lifting (OL), a plyometric (PL), and combined weight lifting + plyometric (WP) training program on vertical jump (VJ) biomechanics. Thirty-six men were assigned randomly to 4 groups: PL group (n = 9), OL group (n = 9), WP group (10), and control (C) group (n = 8). The experimental groups trained 3 dÁwk 21 , for 8 weeks. Sagital kinematics, VJ height, power, and electromyographic (EMG) activity from rectus femoris (RF) and medial gastrocnemius (GAS) were collected during squat jumping and countermovement jumping (CMJ) before and after training. The results showed that all experimental groups improved VJ height (p , 0.05). The OL training improved power and muscle activation during the concentric phase of the CMJ while the subjects used a technique with wider hip and knee angles after training (p , 0.05). The PL group subjects did not change their CMJ technique although there was an increase in RF activation and a decrease of GAS activity after training (p , 0.05). The WP group displayed a decline in maximal hip angle and a lower activation during the CMJ after training (p , 0.05). These results indicate that all training programs are adequate for improving VJ performance. However, the mechanisms for these improvements differ between the 3 training protocols. Olympic weight lifting training might be more appropriate to achieve changes in VJ performance and power in the precompetition period of the training season. Emphasis on the PL exercises should be given when the competition period approaches, whereas the combination of OL and PL exercises may be used in the transition phases from precompetition to the competition period.
Incline plyometrics-induced improvement of jumping performance
European Journal of Applied Physiology, 2011
The aim of this study was to examine the effects of incline plyometrics training on muscle activation and architecture during vertical jumping and maximum strength. Twenty male participants were divided in two training groups which followed after a 4 week training program. The incline plyometrics group (n = 10) trained by performing consecutive jumps on an inclined surface (15°) while the plane plyometrics (PP) group (n = 10) performed the same jumps on a plane surface. Both groups trained four times per week and performed 8 sets of 10 jumps in each session. Subjects performed squat jumps, counter movement jumps and drop jumps (DJ) prior to and immediately after the training period, while the electromyographic activity of the medial gastrocnemius (MGAS) and tibialis anterior muscles and the architecture of MGAS were recorded. Maximal isokinetic and isometric strength of the plantar flexors were performed. Analysis of variance showed that only the IP group improved fast DJ height performance by 17.4 and 14.4% (20 and 40 cm, p \ 0.05). This was accompanied by a significantly higher MGAS activity during the propulsion phase (24% from 20 cm and 50% from 40 cm, p \ 0.05) of the DJ and a longer working fascicle length (5.08%, p \ 0.05) compared with the PP group. There were no significant changes in isokinetic and isometric strength of the plantar flexors after training for both groups. The increase of jumping performance, after incline plyometrics should be taken into consideration by coaches, when they apply hopping exercise to improve explosiveness of the plantar flexors.
Journal of Strength and Conditioning Research, 2009
Saez Saez de Villarreal, E, Kellis, E, Kraemer, WJ, and Izquierdo, M. Determining variables of plyometric training for improving vertical jump height performance: a meta-analysis. J Strength Cond Res 23(2): 495-506, 2009-Plyometric training improves vertical jump height (VJH). However, the effectiveness of plyometric training depends on various factors. A meta-analysis of 56 studies with a total of 225 effect sizes (ESs) was carried out to analyze the role of various factors on the effects of plyometrics on VJH performance. The inclusion criteria for the analysis were a) studies using plyometric programs for lowerlimb muscles, b) studies employing true experimental designs and valid and reliable measurements, and c) studies including enough data to calculate ESs. Subjects with more experience in sport obtained greater enhancements in VJH performance (p , 0.01). Subjects in either good or bad physical condition benefit equally from plyometric work (p , 0.05), although men tend to obtain better power results than women after plyometric training (p , 0.05). With relation to the variables of performance, training volumes of more than 10 weeks and more than 20 sessions, using high-intensity programs (with more than 50 jumps per session), were the strategies that seemed to maximize the probability of obtaining significantly greater improvements in performance (p , 0.05). To optimize jumping enhancement, the combination of different types of plyometrics (squat jump + countermovement jump + drop jump) is recommended rather than using only 1 form (p , 0.05). However, no extra benefits were found to be gained from doing plyometrics with added weight. The responses identified in this analysis are essential and should be considered by strength and conditioning professionals with regard to the most appropriate doseresponse trends for optimizing plyometric-induced gains. R = rest (s); VJG = vertical jump gains (cm). Freq = frequency (dÁwk 21 ); D wk = duration weeks; Int = intensity; H = high; Mod = moderate; BH = box height (cm); No. J = number of jumps; No. E = number of exercises.
Influence of Plyometrics on Jump Capabilities in Technical and Aesthetical Sports
Acta Facultatis Educationis Physicae Universitatis Comenianae, 2017
Summary The aim of the study was to examine the effect of plyometric exercises on explosive strength of lower extremities in girls performing of technical and aesthetical sports. Experiment was carried out on three groups; artistic gymnasts (VG, n = 15; age = 12.4 ± 0.7 years), fitness girls (VF, n = 15; age = 13.8 ± 1.9 years) and dancers (VD, n = 15; age = 13.8 ± 2 years). To check, the control group of general population was involved in the study (VK, n = 15; age = 13.9 ± 1.5 years). Following tests on jump ergometer Fitro Jumper were carried out at the beginning and at the end of experimental period: countermovement jump without and with arms swing and 10- second series of repeated vertical jumps. Plyometric program consisted of two plyometric units a week during thirty weeks. The results show that higher improvement in all evaluated tests achieved the group of fitness. In the countermovement jump without arm swing was observed improvement height of the jump 3.4 ± 1.4 cm (p ˂ 0....
Assessing Plyometric Ability during Vertical Jumps Performed by Adults and Adolescents
Sports
The purpose of this study was to compare different methods for assessing plyometric ability during countermovement (CMJ) and drop jumps (DJ) in a group of adults and adolescents. Ten resistance-trained adult men (age: 22.6 ± 1.6 years) and ten adolescent male basketball players (age: 16.5 ± 0.7 years) performed a CMJ and a DJ from a height of 0.40 m. Jump height (JH), contact time, normalized work (WNORM), and power output (PONORM) during the absorption and propulsion phases were calculated from force platforms and 3-D motion analysis data. Plyometric ability was assessed using the modified reactive strength index (RSIMOD during CMJ) and the reactive strength index (RSI during DJ) as well as three indices using propulsion time, propulsion work (PWI), and propulsion power. Adults jumped significantly higher than adolescents (mean difference [MD]: 0.05 m) while JH (MD: 0.05 m) and ground contact time (MD: 0.29 s) decreased significantly from CMJ to DJ. WNORM (MD: 4.2 J/kg) and PONORM ...