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Purpose: To assess the effect that postexercise immersion in water has on subsequent exercise performance., Methods: A literary search and review of water-immersion and performance studies was conducted., Results: Seven articles were examined. In 2, significant benefits to performance were observed. Those 2 articles revealed a small to large effect on jump performance and isometric strength. PRACTICAL APPLICATION AND CONCLUSIONS: It is possible that water immersion might improve recovery from plyometric or muscle-damaging exercise. Such a statement needs to be verified, however, because of the scarcity of research on water immersion as a recovery strategy.

The purpose of this study was to investigate and compare the acute kinematic, kinetic, and blood lactate responses to continuous and intraset rest loading schemes that differed in terms of rest frequency but not total rest duration. Nine male subjects performed an isoinertial bench press task (6 repetition maximum load) with a continuous, an intraset rest equated by total rest time, volume, and load (ISRV), and an intraset rest equated by total rest time and load (ISRR) loading scheme. The scheme order was assigned in a block-randomized order with a minimum of 48 hours of recovery between testing sessions. Attached to the bar of the Smith machine was a linear position transducer that measured vertical displacement with an accuracy of 0.01 cm. Displacement data was sampled at 1,000 Hz and collected by a laptop computer running custom-built data acquisition software. Finger prick blood lactate samples were taken from the nondominant hand before exercise, immediately after exercise, and 5, 15 and 30 minutes after exercise. Blood glucose samples were taken before exercise only. It was observed that manipulating the rest period, by increasing the frequency but decreasing the length of each rest period, did not significantly influence the kinematics and kinetics associated with resistance training, but did have an effect on the postexercise blood lactate response when the load, rest duration, and training volume were equated (ISRV). This finding may be of practical significance if fatigue is important in strength development or conversely if power training requires minimal fatigue. It was also observed that increasing the frequency of the rest period enabled the subjects to perform a greater number of repetitions (ISRR), resulting in significantly greater kinematics, kinetics, and blood lactate accumulation.

The purpose of this study was to determine the change in weight training repetition power output as a consequence of interrepetition rest intervals. Twenty-six elite junior male basketball and soccer players performed bench presses using a 6 repetition maximum (6RM) load. The power output for each repetition was recorded using a linear encoder sampling each 10 ms (100 Hz). Subjects were assigned to 1 of 3 intervention groups, differentiated by the arrangement of rest intervals within the 6 repetitions: 6 x 1 repetition with 20-second rest periods between each repetition (Singles); 3 x 2 repetitions with 50 seconds between each pair of repetitions (Doubles); or 2 x 3 repetitions with 100 seconds of rest between each 3 repetitions (Triples). A timer was used to ensure that the rest interval and duration to complete all interrepetition interventions was equated across groups (118 seconds). Significantly (p < 0.05) greater repetition power outputs (25-49%) were observed in the later repetitions (4-6) of the Singles, Doubles, and Triples loading schemes. Significantly greater total power output (21.6-25.1%) was observed for all interrepetition rest interventions when compared to traditional continuous 6RM total power output. No significant between-group differences were found (p = 0.96). We conclude that utilizing interrepetition rest intervals enables greater repetition and total power output in comparison to traditional loading parameters.

Recovery from exercise can be an important factor in performance during repeated bouts of exercise. In a tournament situation, where athletes may compete numerous times over a few days, enhancing recovery may provide a competitive advantage. One method that is gaining popularity as a means to enhance post-game or post-training recovery is immersion in water. Much of the literature on the ability of water immersion as a means to improve athletic recovery appears to be based on anecdotal information, with limited research on actual performance change. Water immersion may cause physiological changes within the body that could improve recovery from exercise. These physiological changes include intracellular-intravascular fluid shifts, reduction of muscle oedema and increased cardiac output (without increasing energy expenditure), which increases blood flow and possible nutrient and waste transportation through the body. Also, there may be a psychological benefit to athletes with a reduced cessation of fatigue during immersion. Water temperature alters the physiological response to immersion and cool to thermoneutral temperatures may provide the best range for recovery. Further performance-orientated research is required to determine whether water immersion is beneficial to athletes.

For many sporting activities, initial speed rather than maximal speed would be considered of greater importance to successful performance. The purpose of this study was to identify the relationship between strength and power and measures of first-step quickness (5-m time), acceleration (10-m time), and maximal speed (30-m time). The maximal strength (3 repetition maximum [3RM]), power (30-kg jump squat, countermovement, and drop jumps), isokinetic strength measures (hamstring and quadriceps peak torques and ratios at 60 degrees .s(-1) and 300 degrees .s(-1)) and 5-m, 10-m, and 30-m sprint times of 26 part-time and full-time professional rugby league players (age 23.2 +/- 3.3 years) were measured. To examine the importance of the strength and power measures on sprint performance, a correlational approach and a comparison between means of the fastest and slowest players was used. The correlations between the 3RM, drop jump, isokinetic strength measures, and the 3 measures of sport speed were nonsignificant. Correlations between the jump squat (height and relative power output) and countermovement jump height and the 3 speed measures were significant (r = -0.43 to -0.66, p < 0.05). The squat and countermovement jump heights as well as squat jump relative power output were the only variables found to be significantly greater in the fast players. It was suggested that improving the power to weight ratio as well as plyometric training involving countermovement and loaded jump-squat training may be more effective for enhancing sport speed in elite players.

This study determined the reliability and validity of a linear position transducer to measure jump performance by comparing the mean force, peak force, and time-to-peak force measurements with data obtained simultaneously with a force platform. Twenty-five men performed squat, countermovement, and drop jumps with the linear transducer connected from a waist belt and base, which were placed upon a force platform. The Pearson correlation coefficients across the 3 jumps for the mean force (r = 0.952-0.962), peak force (r = 0.861-0.934), and time-to-peak force (r = 0.924-0.995) were high, providing evidence that the linear-transducer and force-platform measurements were similar. The trial-to-trial reliability of the jumps measured by the linear position transducer gave an intraclass correlation coefficient of 0.924-0.975 for mean force, 0.977-0.982 for peak force, and 0.721-0.964 for time-to-peak force. The coefficients of variation were 2.1-4.5% for mean force, 2.5-8.4% for peak force, and 4.1-11.8% for time-to-peak force. Our findings showed that the calculations derived from the linear transducer were very similar to those of the force platform and hence provided evidence of the validity of this method. The data from the linear transducer were also shown to be reliable. Therefore, this method of calculating force may provide a cost-effective alternative to the force platform for measuring this variable.

Finding assessment methods that are reliable, valid, and easy to administer is important, especially when assessing large numbers of athletes. The purpose of this research therefore was to investigate whether assessment of the upper body using the chest pass throw was significantly related to strength and power as measured using the bench press. The chest pass distance of 12 experienced netball players was measured; thereafter, their bench press 1 repetition maximum and various kinematic and kinetic variables were calculated from a 10-kg bench press throw performed on an instrumented Smith machine. Pearson correlation coefficients were used to establish the relationship between the strength/power variables and the chest pass. Of the kinematic and kinetic variables calculated from the bench press throws, impulse and power were the variables most highly correlated to chest pass distance (r = 0.775-0.810), whereas the measures of initial force production (F30ms and F100ms) were the lowest (r = 0.082-0.105). Four variables had a greater than 50% (R2) shared variance with the netball chest pass-impulse, peak power, mean power and maximal strength. Power and impulse are strong predictors of chest pass performance; however, the value of the chest pass as an assessment tool to map strength and power changes in an athlete needs to be investigated using a training study approach.

The purpose of this study was to investigate whether changes in maximal strength and power output occurred over time in the absence of strength and power training in novice weight trainers. It also investigated whether differences existed between upper- and lower-body assessments and unilateral and bilateral assessments. The power output and maximal strength (1 repetition maximum [1RM]) of 10 male novice subjects were measured on 4 occasions, each assessment 7-10 days apart. The exercises used to measure the upper- and lower-body strength and power outputs were the bench press and supine squat, respectively. Significant (p < 0.05) changes in unilateral (9.8-16.8%) and bilateral 1RM (6.8-15.0%) leg strength were found, the first assessment being significantly different from all other assessments and assessment 2 significantly different from assessment 4. Changes in the upper body (10-13.6%) were also observed. The only significant difference was between assessment 1 and the other testing occasions. No differences in power output were observed for both the upper and lower body during the study. It would seem that considerable changes in maximal strength occur rapidly and in the absence of any formal strength training program in novice weight trainers.

The purpose of this study was to investigate the force-velocity response of the neuromuscular system to a variety of concentric only, stretch-shorten cycle, and ballistic bench press movements. Twenty-seven men of an athletic background (21.9 +/- 3.1 years, 89.0 +/- 12.5 kg, 86.3 +/- 13.6 kg 1 repetition maximum [1RM]) performed 4 types of bench presses, concentric only, concentric throw, rebound, and rebound throw, across loads of 30-80% 1RM. Average force output was unaffected by the technique used across all loads. Greater force output was recorded using higher loading intensities. The use of rebound was found to produce greater average velocities (12.3% higher mean across loads) and peak forces (14.1% higher mean across loads). Throw or ballistic training generated greater velocities across all loads (4.4% higher average velocity and 6.7% higher peak velocity), and acceleration-deceleration profiles provided greater movement pattern specificity. However, the movement velocities (0.69-1.68 m.s(-1)) associated with the loads used in this study did not approach actual movement velocities associated with functional performance. Suggestions were made as to how these findings may be applied to improve strength, power, and functional performance.

A variable considered when designing programs to optimize athletic performance is training velocity. It has been suggested that training at a specific velocity improves strength mainly at that velocity and as velocity deviates from the trained velocity, the less effective training will be. However, the research describing velocity-specific adaptation and the transference of these adaptations to other movement velocities is by no means clear. Compounding the problem in this area is the failure of research to detail the relationship between training velocity and actual movement velocity of a given task or athletic pursuit. In most cases there is a great disparity between training velocity and actual movement velocity. Factors that may better develop and explain velocity-specific adaptation in relation to functional performance are discussed. Developing qualities such as strength, power and rate of force development would appear of greater importance than training at the actual movement velocity of a task. It may be that irrespective of load and limb velocity, the repeated intent to move an isoinertial load as rapidly as possible might be an important stimulus for functional high velocity adaptation. The ability of the nervous system to activate and coordinate agonist, synergist and antagonist activity would seem essential. It was suggested training techniques that simulate the velocity and acceleration profiles associated with the desired functional performance, such as throw or jump training, may optimize functional adaptation. Furthermore combination training that incorporates same session sport specific training with either a heavy load or a mixed training load approach might provide an optimal strategy for promoting intramuscular and intermuscular co-ordination and improving functional performance.

The purpose of this study was to determine the important predictors of power absorption and power production during slow, large-amplitude stretch-shorten cycle (SSC) motions. The relationship between power absorption (mean eccentric power output) and production (mean concentric power output) across different inertial loads was also investigated. Fifty-four subjects with a sporting background performed concentric (CBP) and rebound bench-presses (RBP) at 40% and 80% of their one-repetition maximum (1RM). The relationship between kinematic and kinetic variables and mean eccentric power and RBP mean power output was determined using correlation and multiple regression analysis. Maximal strength was found to be the best single predictor of power absorption, explaining between 44.2% and 69.1% of the variability that was associated with mean eccentric power output for 40% and 80% 1RM loads. Stretch velocity in combination with maximal strength was found to be the best two-predictor model of power absorption ( R(2)=83.7-97.3%). The best single predictor of SSC power production was found to be concentric mean power output ( R(2)=49.2-88.0%). The utilisation of the power absorbed during the power production phase differed across loads. It was suggested that as maximal strength is more trainable than speed, training to improve power absorption might emphasise maximal strength development. It was also suggested that SSC power output might benefit from training methods that focus on concentric force development. Further research is needed to evaluate these hypotheses and whether the findings of this study are similar for fast SSC motion.

There is ample evidence that the pre-stretching of a muscle enhances performance of the subsequent shortening or concentric contraction. The purpose of this study was to investigate this stretch-induced enhancement in terms of the effect of load on the magnitude and decay of the muscle's power output. Instantaneous, mean and peak power outputs were compared between concentric-only and rebound bench press throws at different loads. The maximal strength [1 RM = 84.0 (10.5) kg] of 18 male subjects [21.1 (3.0) years, 87.2 (11.9) kg] was determined using an isoinertial Smith press machine. The results of this study indicate enhancement of concentric motion by prior eccentric muscle action (200-780% enhancement in the first 100 ms). However, the magnitude and temporal characteristics of this enhancement differed across loads. Using a lighter load produced greater initial enhancement (P < 0.05) but the decay of this enhancement was more rapid. The heavier 80% 1 RM loading showed a later time to peak enhancement (80 ms versus 20 ms) and slower decay of the stretch induced augmentation (460 ms versus 260 ms). It is concluded that the degree of stretch-shorten cycle enhancement differs according to the load and the time-dependent characteristics of the motion.