Two Days Versus Four Days of Training Cessation Following a Step-Taper in Powerlifters

ABSTRACT

Burke, BI, Carroll, KM, Travis, SK, Stone, ME, and Stone, MH. Two days versus four days of training cessation following a step-taper in powerlifters. J Strength Cond Res 37(12): e625-e632, 2023-Tapering and training cessation are methods of training load management aimed at optimizing athlete preparedness leading into competition. Such practices are often used by strength sport athletes such as powerlifters (i.e., athletes who compete in the back squat [BS], bench press [BP], and deadlift [DL]). The purpose of this study was to compare the differences in maximal strength, subjective recovery and stress state, and body composition alterations in strength athletes undergoing a 1-week step-taper followed by either a 2-day (2D) or 4-day (4D) period of training cessation. Twelve powerlifters (22.3 ± 2.1 yrs; 92.1 ± 20.4 kg; 174.8 ± 7.5 cm) completed a 6-week training protocol aimed at peaking 1 repetition maximum (1RM) strength on BS, BP, and DL. Body composition, subjective recovery and stress state, and 1RM on BS, BP, and DL were assessed before an overreach week (T1) and after the periods of training cessation (T2) for each group. Alpha criterion was set at p ≤ 0.05. There were significant increases in BP ( p = 0.032, g = 0.10), powerlifting total ( p = 0.014, g = 0.11), and DOTS score ( p = 0.006, g = 0.12) after 2D of cessation. However, after 4D of cessation, significant increases were only observed in DL ( p = 0.019, g = 0.11) along with significant decreases in BP ( p = 0.003, g = -0.13). There were no statistically significant changes in any other variable for either group indicating that BS, psychometric, and body composition data were maintained between T1 and T2. The results of this study support the use of 1-week step-tapers, followed by a short period of training cessation (2-4D) to maintain or improve maximal strength performance.

Acute caffeine supplementation enhances several aspects of shot put performance in trained athletes

The aim of this investigation was to determine the effect of a moderate dose of caffeine (3 mg/kg/b.m.) on muscular power and strength and shot put performance in trained athletes. Methods. Thirteen shot putters (eight men and five women) participated in a double-blind, placebo-controlled, randomized experiment. In two different trials, participants ingested either 3 mg/kg/b.m. of caffeine or a placebo. Forty-five min after substance ingestion, athletes performed a handgrip dynamometry test, a countermovement jump (CMJ), a squat jump (SJ), and a maximum-velocity push-up. The athletes also performed three types of throws: a backwards throw, a standing shot put and a complete shot put. Results. In comparison with the placebo, caffeine ingestion increased CMJ height (32.25 ± 7.26 vs. 33.83 ± 7.72 cm, respectively; effect size (ES) = 0.82, p = 0.012; +5.0%;) and SJ height (29.93 ± 7.88 vs. 31.40 ± 7.16 cm; ES = 0.63, p = 0.042; +6.4%) and distance in the standing shot put (10.27 ± 1.77 m vs. 10.55 ± 1.94 m; ES = 0.87, p = 0.009; +2.6%). However, caffeine ingestion did not increase strength in the handgrip test, power in the ballistic push-up, or distance in the backwards throw (all p > 0.05). Shot put performance changed from 11.24 ± 2.54 to 11.35 ± . 2.57 m (ES = 0.33, p = 0.26; +1.0%), although the difference did not reach statistically significant differences. Caffeine ingestion did not increase the prevalence of side effects (nervousness, gastrointestinal problems, activeness, irritability, muscular pain, headache, and diuresis) in comparison with the placebo (p > 0.05). Conclusion. In summary, caffeine ingestion with a dose equivalent to 3 mg/kg/b.m. elicited moderate improvements in several aspects of physical performance in trained shot putters but with a small effect on distance in a complete shot put.

Effects of Complex Vs. Compound Training on Competitive Throwing Performance

ABSTRACT

Thomas, K, Spyridon, M, Nikolaos, Z, Angeliki-Nikolleta, S, Giorgos, K, Giorgos, G, and Gerasimos, T. Effects of complex vs. compound training on competitive throwing performance. J Strength Cond Res XX(X): 000-000, 2022-The purpose of this study was to investigate the effects of complex (CPX; strength and power exercises in pairs) vs. compound (CPD; strength and power exercises in different days) training on competitive track and field throwing performance. Ten well-trained throwers (7 male throwers and 3 female throwers) followed a 34-week periodized training program including 2 preparation periods. During the winter 4-week, precompetition phase, athletes were randomly assigned to CPX or CPD groups, while the opposite assignment was performed during the spring precompetition phase (counterbalanced design). Before and after each training period competitive track and field throwing performance, shot put throws, snatch, squat and bench press 1 repetition maximum (1RM), vertical jumps, rate of force development (RFD), and body composition were evaluated. Competitive track and field throwing performance increased significantly by 5.4 ± 2.9% and 1.9 ± 1.7%, after CPX and CPD, respectively, with a significant difference between groups (p < 0.001). Shot put throws and 1RM strength in bench press increased similarly after both programs (p < 0.05), but vertical jumps increased only after CPX training. CPX induced greater increases in 1RM strength in snatch and squat, RFD, and lean body mass compared with CPD (p < 0.005). The linear combination of training-induced changes in RFD 150ms, 1RM in squat, snatch, and total lean mass explained the 80% of the percentage increase in competitive track and field throwing performance (p = 0.007). These results suggest that 4 weeks of CPX training during the precompetition period induce greater increases in competitive track and field throwing performance, 1RM strength, power, and RFD compared with CPD training.

Effects of a 25-Week Periodized Training Macrocycle on Muscle Strength, Power, Muscle Architecture, and Performance in Well-Trained Track and Field Throwers

ABSTRACT

Anousaki, E, Zaras, N, Stasinaki A-N, Panidi, I, Terzis, T, and Karampatsos, G. Effects of a 25-week periodized training macrocycle on muscle strength, power, muscle architecture, and performance in well-trained track and field throwers. J Strength Cond Res 35(10): 2728-2736, 2021-The purpose of the study was to investigate the effect of a 25-week macrocycle on strength, power, vastus lateralis (VL) muscle architecture, and competitive track and field throwing performance, in well-trained track and field throwers. Twelve well-trained throwers (age: 24.3 ± 5.5 years, mass: 96.6 ± 9.9 kg, and height: 1.82 ± 0.02 m), participated in the study. All athletes followed a 25-week periodized training program divided into 3 training phases: the hypertrophy/maximum strength phase, the maximum strength/power phase, and the power/speed phase. Measurements were performed at the beginning of the training period (T1), after the first training phase (T2), and after the end of the training period (T3). Measurements included the following: competitive track and field throwing performance; shot put throws; maximum strength (1-RM) in snatch, clean, and squat; countermovement jump (CMJ); and VL muscle architecture. Competitive track and field throwing performance and shot put throws increased from T1 to T3 by 10.9 ± 3.2% (p = 0.001) and 5.1 ± 6.4% (P = 0.049), respectively. 1 RM strength in snatch and squat increased significantly from T1 to T3 by 9.7 ± 8.9% (p = 0.001) and 9.9 ± 7.1% (p = 0.002), respectively. Countermovement jump height increased only from T1 to T2 by 10.9 ± 11.8% (p = 0.026). A significant increase was found for VL fascicle length between T1 and T3 (9.6 ± 11.1%, p = 0.049). Strong correlations were found between the percentage increase of competitive track and field throwing performance with 1 RM snatch (r = 0.571, p = 0.046) and with shot put throws (r = 0.715, p = 0.001). Twenty five weeks of training may increase performance and VL fascicle length, whereas increases in 1 RM snatch and in shot put throws are associated with competitive track and field throwing performance in well-trained throwers.

Biological Determinants of Track and Field Throwing Performance

Track and field throwing performance is determined by a number of biomechanical and biological factors which are affected by long-term training. Although much of the research has focused on the role of biomechanical factors on track and field throwing performance, only a small body of scientific literature has focused on the connection of biological factors with competitive track and field throwing performance. The aim of this review was to accumulate and present the current literature connecting the performance in track and field throwing events with specific biological factors, including the anthropometric characteristics, the body composition, the neural activation, the fiber type composition and the muscle architecture characteristics. While there is little published information to develop statistical results, the results from the current review suggest that major biological determinants of track and field throwing performance are the size of lean body mass, the neural activation of the protagonist muscles during the throw and the percentage of type II muscle fiber cross-sectional area. Long-term training may enhance these biological factors and possibly lead to a higher track and field throwing performance. Consequently, coaches and athletes should aim at monitoring and enhancing these parameters in order to increase track and field throwing performance.

The effect of athletic throwing events on the body composition and bone density in the limbs of throwing athletes

BACKGROUND

Throwing and putting are technical athletic events where one upper limb is dominant. The different load on the preferred and non-preferred limb may influence the body composition of the upper limb segments. The objective of the study is to assess the difference between the throwing and non-throwing upper limb in athletes specializing in javelin throw and shot put based on the segmental body composition analysis and kinetic analysis.

METHODS

The group included 16 throwers at the age of 17.5±2.4 years. As a control group, we used 16 jumper athletes (age of 17.7±2.6 years). The symmetry of the load on upper limbs during a push-up was provided by the kinetic motion analysis. The segmental analysis of the upper limb body composition parameters was implemented using the method of dual X-ray absorptiometry.

RESULTS

As to the power parameters, symmetry between the throwing and non-throwing upper limbs during the performance of a push-up was observed. The analysis of the upper limb body mass distribution showed statistically and objective significance in the bone mass values. The ratio of bone mass was higher in the throwing upper limb by 0.02 kg (P<0.0001) and bone density was higher by 0.07 g/cm2 (P<0.0001), the practical significance of the differences was major change for BMC (d=0.8) and medium for BMD (d=0.5).

CONCLUSIONS

The results imply that the throw is a significant factor that contributes to the formation of bone mass.

Tapering and Peaking Maximal Strength for Powerlifting Performance: A Review

Prior to major competitions, athletes often use a peaking protocol such as tapering or training cessation to improve performance. The majority of the current literature has focused on endurance-based sports such as swimming, cycling, and running to better understand how and when to taper or use training cessation to achieve the desired performance outcome. However, evidence regarding peaking protocols for strength and power athletes is lacking. Current limitations for peaking maximal strength is that many studies do not provide sufficient details for practitioners to use. Thus, when working with athletes such as powerlifters, weightlifters, throwers, and strongman competitors, practitioners must use trial and error to determine the best means for peaking rather than using an evidence-based protocol. More specifically, determining how to peak maximal strength using data derived from strength and power athletes has not been established. While powerlifting training (i.e., back squat, bench press, deadlift) is used by strength and power athletes up until the final days prior to a competition, understanding how to peak maximal strength relative to powerlifting performance is still unclear. Thus, the purpose of this study was to review the literature on tapering and training cessation practices relative to peaking powerlifting performance.

Validation of an inertial measurement unit to determine countermovement jump height

Background

Vertical jump highs are used to quantify performance in the lower extremities. The aim of this study was to validate a wearable inertial measurement unit (IMU) for purpose of estimating countermovement jump height using the following methods: numerical double integration (NDI), takeoff velocity (TOV) and flight-time (FT).

Methods

Fifteen students each performed three jumps in two different sessions, four weeks apart. Jump-heights calculated from motion capture and force plate were used as gold standard for global IMU position and center of mass (CoM) displacement, respectively.

Results

The NDI method showed higher estimates for global position (1.39 cm, p = 0.025), and for CoM displacement (4.20 cm, p < 0.001). Narrow limits of agreements (LoA) were found (<4.8 cm). Further, a low tolerance level of determining equivalence (delta) between the two sessions regarding both global and CoM displacement (±2.80 and ± 2.90 cm) suggesting reasonable test-retest reliability.Similar bias was found for TOV and FT (p < 0.015) and wide LoAs were found for global position and for CoM displacement (TOV: ±7.05 and ± 9.36 cm, AT: ±9.27 and ± 8.49 cm). Further, high delta between the two sessions (TOV: ±3.50 cm, FT ±4.00 cm) showed poor test-retest reliability.

Conclusion

Estimation of countermovement jump height using an IMU leads to the most accurate measurements applying the NDI-method. Countermovement jump estimated with an IMU can reliably evaluate functional performance in the lower extremities in young or in sports active patients after surgery or after rehabilitation. Countermovement jump with an IMU allows performing the test without a force plate and thus serves as an objective outcome measure in clinical practice.

Acute Effect of Upper and Lower Body Postactivation Exercises on Shot Put Performance

Kontou, EI, Berberidou, FT, Pilianidis, TC, Mantzouranis, NI, and Methenitis, SK. Acute effect of upper and lower body postactivation exercises on shot put performance. J Strength Cond Res 32(4): 970-982, 2018-The purpose of this study was to investigate the effect of different types of upper and lower' extremities exercises on acute increase of shot put performance, in moderate experienced throwers. Eight (n = 8) males and 9 (n = 9) female throwers participated in this study. Their bench press and squat maximum strength were measured while their shot put performance from power position was evaluated before and after 4 interventions: (a) plyometric push-ups (Plyo), (b) 6 s isometric push-ups (Iso), (c) 3 countermovement jumps (CMJs) and (d) 10 reps. of skipping (Skip). Interventions were performed in counterbalanced order with a 48-hour interval. Significant increase (p < 0.05) of shot put performances was observed after Plyo, Iso, and CMJ (range: 2.30 ± 1.82%-5.72 ± 4.32%). In addition, Iso induced the highest increase while Skip did not induce any improvement of throwing performance. The highest increases were recorded in men's performance after CMJ (5.72 ± 4.32%) while in women's performance after Iso (3.59 ± 2.7%). Javelin and discus throwers increase higher their performance after CMJs while shot putters after Iso. Significant correlations were found between training experience, maximum/relative strength, shot put performance and increase of throwing performance (%) after the interventions (r: 0.519-0.991, p < 0.05). Percentage increase of performance between Iso and Plyo have negative correlations (r: -0.569, p < 0.05) in contrast of those between Skip and CMJ (r: 0.710, p < 0.05). These results suggest that upper or lower body postactivation interventions may acutely increase the throwing performance. However, experience and strength are significant determinant of this increase.

Kinematic analysis of the shot-put: A method of assessing the mechanical work of the hand action force

The aims of this study were to (1) propose a method for evaluating shot-putters mechanical power, (2) investigate the relationship between mechanical work of hand action force (W_HAF), peak power output (PPO) of different limbs and shot-put performance and (3) show which of these two parameters (W_HAF, PPO) were the most appropriate to characterize the explosive abilities of the shot-putter. Twelve junior right-handed shot-putters, practised glide technique shot-put throwers (personal best = 13.57  ±  1.72 m), participated in this study. Arm and leg force-velocity tests were performed to measure PPO. Kinematic analysis was conducted during a shot-putting event in regular conditions to quantify the W_HAF at the release moment and shot-put performance. Significant correlations were found between absolute arm and leg PPO with upper and lower muscle volumes (r = .67; p = .03; r = .76; p = .01; r = .74, p = .01; r = .65, p = .04). Positive relationships were recorded between absolute arm and leg PPO and shot-put performance (r = .67, p = .02; r = .81, p = .004, respectively). Shot-put performance was also closely related to the W_HAF (r = .93, p = .0001) and release velocity parameter (r = .86, p = .001). The present results confirm that force-velocity test and W_HAF constitute useful tools for assessing mechanical power in throwing. The W_HAF could be considered as more suitable than force-velocity test.

Muscle activation sequencing of leg muscles during linear glide shot putting

In the shot put, the athlete's muscles are responsible for generating the impulses to move the athlete and project the shot into the air. Information on phasic muscle activity is lacking for the glide shot put event and therefore important technical information for coaches is not currently available. This study provides an electromyography (EMG) analysis of the muscle activity of the legs during shot put. Fifteen right-handed Irish national level shot putters performed six maximum effort throws using the glide shot put technique. EMG records of eight bilateral lower limb muscles (rectus femoris, biceps femoris, medial- and lateral-gastrocnemius) were obtained during trials. Analysis using smooth EMG linear envelopes revealed patterns of muscle activity across the phases of the throw and compare men and women performers. The results showed that the preferred leg rectus femoris, the preferred leg biceps femoris and the non-preferred leg biceps femoris play important roles in the glide technique, with the total duration of high volumes of activity between 34 and 53% of the throw cycle. A comprehensive understanding of movement and muscle activation patterns for coaches could be helpful to facilitate optimal technique throughout each of the key phases of the event.

Body Composition and Muscle Characteristics of Division I Track and Field Athletes

The purpose of this study was to evaluate event-specific body composition and muscle characteristics of track and field athletes and to assess body composition changes after 1 year. Sixty collegiate track and field athletes (mean ± SD; age = 19.2 ± 1.4 years, height = 174.6 ± 9.0 cm, and weight = 71.5 ± 12.5 kg) were stratified into 6 event groups. Total and regional body composition measurements were assessed using dual-energy x-ray absorptiometry. A panoramic scan of the vastus lateralis was taken with B-mode ultrasound to determine muscle cross-sectional area and echo intensity (EI). Body composition measurements were repeated a year later in a subset of returning athletes (n = 33). Throwers had significantly more absolute fat mass (FM; 21.6 ± 11.0 kg), total body mass (89.7 ± 17.4 kg), percent fat (23.6 ± 7.8), and trunk fat (9.4 ± 5.8 kg) than all other event groups (p ≤ 0.05). Throwers had the most absolute lean mass (LM; 64.2 ± 11.7 kg; p > 0.05), but relative to body mass had relatively less LM (0.72 ± 0.08 kg; p ≤ 0.05). Despite high FM, throwers had lower EI (63.4 ± 5.2 a.u). After 1 year, relative armLM increased slightly in all event groups (p ≤ 0.05). Evaluation of muscle characteristics in addition to total and regional body composition may be valuable for improving performance, injury prevention, and assessing health risks. With appropriate training, track and field athletes may be able to minimize losses in LM and gains in FM between seasons.

Measurement errors when estimating the vertical jump height with flight time using photocell devices: the example of Optojump

Common methods to estimate vertical jump height (VJH) are based on the measurements of flight time (FT) or vertical reaction force. This study aimed to assess the measurement errors when estimating the VJH with flight time using photocell devices in comparison with the gold standard jump height measured by a force plate (FP). The second purpose was to determine the intrinsic reliability of the Optojump photoelectric cells in estimating VJH. For this aim, 20 subjects (age: 22.50±1.24 years) performed maximal vertical jumps in three modalities in randomized order: the squat jump (SJ), counter-movement jump (CMJ), and CMJ with arm swing (CMJarm). Each trial was simultaneously recorded by the FP and Optojump devices. High intra-class correlation coefficients (ICCs) for validity (0.98-0.99) and low limits of agreement (less than 1.4 cm) were found; even a systematic difference in jump height was consistently observed between FT and double integration of force methods (-31% to -27%; p<0.001) and a large effect size (Cohen's d>1.2). Intra-session reliability of Optojump was excellent, with ICCs ranging from 0.98 to 0.99, low coefficients of variation (3.98%), and low standard errors of measurement (0.8 cm). It was concluded that there was a high correlation between the two methods to estimate the vertical jump height, but the FT method cannot replace the gold standard, due to the large systematic bias. According to our results, the equations of each of the three jump modalities were presented in order to obtain a better estimation of the jump height.

Role of Muscle Morphology in Jumping, Sprinting, and Throwing Performance in Participants With Different Power Training Duration Experience

The aim of the study was to examine the correlation between muscle morphology and jumping, sprinting, and throwing performance in participants with different power training duration experience. Thirty-six power-trained young men were assigned to 3 groups according to the length of their power training: less experienced (<1 year), moderately experienced (1-3 years), and experienced (4-7 years). All participants performed countermovement and squat jumps, 60-m sprint, and shot throws twice. Lean body mass (LBM) was evaluated with dual-energy x-ray absorptiometry and thigh muscle cross-sectional area (CSA) with anthropometry. The vastus lateralis architecture and fiber type composition were evaluated with ultrasonography and muscle biopsies, respectively. When all subjects were considered as 1 group (n = 36), jumping performance was correlated with LBM, fascicle length, and type II fiber CSA; sprinting performance was correlated with estimated thigh muscle CSA alone; and shot throwing was correlated with LBM and type I, IIA fiber CSA. In the least experienced group, the LBM of the lower extremities was the most significant contributor for power performance, whereas in the moderately experienced group, the LBM, architectural properties, and type II fiber percentage CSA were the most significant contributors. For the experienced group, fascicle length and type II fiber percentage CSA were the most significant factors for power performance. These data suggest that jumping performance is linked with muscle morphology, regardless of strength or power training. The vastus lateralis muscle morphology could only partially explain throwing performance, whereas it cannot predict sprinting performance. Power performance in experienced participants rely more on the quality of the muscle tissue rather than the quantity.

Effects of tapering with light vs. heavy loads on track and field throwing performance

The purpose of the study was to investigate the effects of power training with light vs. heavy loads during the tapering phases of a double periodized training year on track and field throwing performance. Thirteen track and field throwers aged 16-26 years followed 8 months of systematic training for performance enhancement aiming at 2 tapering phases during the winter and the spring competition periods. Athletes performed tapering with 2 different resistance training loads (counterbalanced design): 7 athletes used 30% of 1 repetition maximum (1RM) light-load tapering (LT), and 6 athletes used the 85% of 1RM heavy-load tapering (HT), during the winter tapering. The opposite was performed at the spring tapering. Before and after each tapering, throwing performance, 1RM strength, vertical jumping, rate of force development (RFD), vastus lateralis architecture, and rate of perceived exertion were evaluated. Throwing performance increased significantly by 4.8 ± 1.0% and 5.6 ± 0.9% after LT and HT, respectively. Leg press 1RM and squat jump power increased more after HT than LT (5.9 ± 3.2% vs. -3.4 ± 2.5%, and 5.1 ± 2.4% vs. 0.9 ± 1.4%, respectively, p ≤ 0.05). Leg press RFD increased more in HT (38.1 ± 16.5%) compared with LT (-2.9 ± 6.7%), but LT induced less fatigue than HT (4.0 ± 1.5 vs. 6.7 ± 0.9, p ≤ 0.05). Muscle architecture was not altered after either program. These results suggest that performance increases similarly after tapering with LT or HT in track and field throwers, but HT leads to greater increases in strength, whole body power, and RFD.

Reliability and validity of a talent identification test battery for seated and standing Paralympic throws

Paralympic throwing events for athletes with physical impairments comprise seated and standing javelin, shot put, discus and seated club throwing. Identification of talented throwers would enable prediction of future success and promote participation; however, a valid and reliable talent identification battery for Paralympic throwing has not been reported. This study evaluates the reliability and validity of a talent identification battery for Paralympic throws. Participants were non-disabled so that impairment would not confound analyses, and results would provide an indication of normative performance. Twenty-eight non-disabled participants (13 M; 15 F) aged 23.6 years (±5.44) performed five kinematically distinct criterion throws (three seated, two standing) and nine talent identification tests (three anthropometric, six motor); 23 were tested a second time to evaluate test-retest reliability. Talent identification test-retest reliability was evaluated using Intra-class Correlation Coefficient (ICC) and Bland-Altman plots (Limits of Agreement). Spearman's correlation assessed strength of association between criterion throws and talent identification tests. Reliability was generally acceptable (mean ICC = 0.89), but two seated talent identification tests require more extensive familiarisation. Correlation strength (mean rs = 0.76) indicated that the talent identification tests can be used to validly identify individuals with competitively advantageous attributes for each of the five kinematically distinct throwing activities. Results facilitate further research in this understudied area.

Muscle strength, body composition, and performance of an elite shot-putter

PURPOSE

Although muscle mass and strength are thought to be closely related to throwing performance, there are few scientific data about these parameters in elite shot-putters. The purpose of this case report was to present longitudinal data for muscle strength and body composition in relation to performance of an elite male shot-putter.

METHODS

A male national champion with the best rotational shot-put performance of 20.36 m (in 2010) was followed from 2003 to 2011 (current age: 29 y). Data regarding body composition (dual X-ray absorptiometry), as well as 1-repetition-maximum muscle strength (bench press, squat, snatch) and rotational shot-put performance, were collected every February for the last 9 y, 4 wk before the national indoor championship event.

RESULTS

The athlete's personal-best performances in squat, bench press, and snatch were 175 kg, 210 kg, and 112.5 kg, respectively. His peak total lean body mass was 92.4 kg, bone mineral density 1.55 g/cm2, and lowest body fat 12.9%. His shot-put performance over these 9 years was significantly correlated with 1-repetition-maximum squat strength (r = .93, P < .01), bench press (r = .87, P < .01), and snatch (r = .92, P < .01). In contrast, shot-put performance was not significantly correlated with any of the body-composition parameters.

CONCLUSIONS

The results of this case study suggest that elite rotational shot-put performance may not be directly correlated with lean body mass. Instead, it seems that it is closely related with measures of muscle strength.

Validity of two methods for estimation of vertical jump height

The objectives of this study were (a) to determine the concurrent validity of the flight time (FT) and double integration of vertical reaction force (DIF) methods in the estimation of vertical jump height with the video method (VID) as reference; (b) to verify the degree of agreement among the 3 methods; (c) to propose regression equations to predict the jump height using the FT and DIF. Twenty healthy male and female nonathlete college students participated in this study. The experiment involved positioning a contact mat (CTM) on the force platform (FP), with a video camera 3 m from the FP and perpendicular to the sagittal plane of the subject being assessed. Each participant performed 15 countermovement jumps with 60-second intervals between the trials. Significant differences were found between the jump height obtained by VID and the results with FT (p ≤ 0.01) and DIF (p ≤ 0.01), showing that the methods are not valid. Additionally, the DIF showed a greater degree of agreement with the reference method than the FT did, and both presented a systematic error. From the linear regression test was determined the prediction equations with a high degree of linearity between the methods VID vs. DIF (R = 0.988) and VID vs. FT (R = 0.979). Therefore, the prediction equations suggested may allow coaches to measure the vertical jump performance of athletes by the FT and DIF, using a CTM or an FP, which represents more practical and viable approaches in the sports field; comparisons can then be made with the results of other athletes evaluated by VID.

Body composition and performance in shot put athletes at preseason and at competition

PURPOSE

The purpose of the current study was to investigate the relationship between fat-free mass and shot put performance at the beginning of the winter preparation cycle and at the first peak of the season (12 wk later) in well-trained shot-putters using the rotational style.

METHODS

Eight national-level shot put athletes followed their individual training programs for a period of 12 wk aiming at the national indoor championship. Shot put performance with the rotational style as well as from the power position was determined before and after this 12 wk period. Body composition was determined before and after the training period with dual x-ray absorptiometry.

RESULTS

Shot put from the power position was increased by 3% (P = .03) while shot put with the rotational style was increased by 6.5% (P < .01). Fat-free mass, body fat and bone mineral density were not altered after the training period. The correlation coefficient between fat-free mass and shot put performance from the power position was significant (r = .76 preseason vs r = .66, competition; P < .05). The correlation coefficient between fat-free mass and shot put performance with the rotational style was significant at the beginning of the training period (r = .70, P < .05) but it was decreased to moderate and nonsignificant levels at competition (r = .55, ns).

CONCLUSIONS

These results suggest that the increase of fat-free mass might not be the most essential element for competition when the rotational shot put style is involved.