The effects of post-activation performance enhancement and different warm-up protocols on swim start performance.

This study aimed to examine the effects of post-activation performance enhancement (PAPE) on swim start performance and lower body power performance after different warm-up protocols. Ten male national-level swimmers performed three different warm-ups: (i) a swim-specific warm-up (SW, control protocol); (ii) PAPE (an experimental protocol); and (iii) SW followed by PAPE (SW + PAPE, an experimental protocol). PAPE consisted of performing three series of 5 drop jumps. A repeated-measures ANOVA showed significant differences between the protocols in the swim start performance (F = 8.89; P < 0.001) and countermovement jump (F = 2.22; P = 0.047). SW + PAPE induced greater improvements in swim start time to 15 m (ES = - 0.47, P = 0.017) and entry time (ES = - 1.83, P < 0.001), the countermovement jump reactive strength index modified (ES = - 1.83, P < 0.001), eccentric rate of force development (ES = 0.69, P = 0.047), and index of explosive strength (ES = 0.94, P = 0.005) compared to SW. The current findings of this study indicate that the drop jump PAPE protocol, in addition to SW, is an effective tool because it could improve athletes' capacity for a more efficient swim start and their countermovement jump performance. Furthermore, the results of this study indicate that PAPE induced by drop jumps could be time-efficient and practically applicable in facilities with limited resources.

Relations between lower body isometric muscle force characteristics and start performance in elite male sprint swimmers.

The aim of the present study was twofold. The first aim was to examine the influence of absolute and relative lower body muscle force on kinematic component which determine the start performance. The second aim was to create multiregressional model which could use as a tool for swimming coaches with the purpose to start performance control and improvement. Twenty seven high-level trained male competitive swimmers all members of the Serbian National Youth and Senior Swimming Team (Age = 21.1 ± 4.3 yrs., Height = 1. 89 ± 0.10 m, Weight = 81.6 ± 8.4 kg, 50m freestyle - long course = 24.36 ± 0.86 s) performed two trials of standing leg extensors isometric muscle force testing and three swimming start trials corresponding to 10m distance. The average start time significantly correlated with variables of leg extensors maximum voluntary force (Fmax, r = -0.559, p = 0.002), leg extensors relative muscle voluntary force (Frel, r = -0.727, p < 0.001), leg extensors specific rate of force development (RFD50%, r = -0.338, p = 0.047) and leg extensors relative value of specific rate of force development (RFD50%rel, r = -0.402, p = 0.040). Regression equation for t10m prediction was defined by following variables: maximum voluntary isometric force of leg extensors muscles at absolute and relative level (Fmax and Frel), as well as a specific rate of force development of the same muscle groups (RFD50% and RFD50%rel) at absolute and relative level too with 74.4% of explained variance. Contractile abilities indicators of the leg extensors muscles included consideration: Fmax, RFD50%, Frel and RFD50%rel showed significant correlation with swimming start times on 10m. Additionally, the results suggest that swimmers, who possess greater isometric maximum force and specific rate of force development at absolute and relative levels, tend to be able to swim faster on initial 10m swim start perforamnce. Key PointsIn high-level male swimmers:Leg extensors maximum voluntary force, leg exten-sors relative value of maximum muscle voluntary force, leg extensors specific rate of force develop-ment and leg extensors relative value of specific rate of force development positively associated with the start time measured on 10m-mark.Time at 10m-mark was not associated with legs ex-tensors basic level of rate of force development at absolute and relative level.Obtained multi-regressional model is defined by variables which measure the development of maxi-mum voluntary isometric leg extensor muscle force on the absolute and relative level, as well as vari-ables which measure the development of specific explosive force of the same muscle group on abso-lute and relative level, this could use as a tool for swimming coaches to control the direction and ex-tent of development of a given force characteristics for providing conditions for start improvement in highly trained elite male sprint swimmers.

Differences in the efficiency between the grab and track starts for both genders in greek young swimmers.

The aim of this study was to determine the differences in the kinematic parameters between the grab and track starts and the differences in these two starts between genders. A total of 27 swimmers at the competitive level participated in the study, 13 boys (mean ± SD: age 15.8 ± 0.8 years, body mass 67.7 ± 7.7 kg and body height 178.6 ± 5.7 cm) and 14 girls (mean ± SD: age 16 ± 0.8 years, body mass 59.2 ± 6.6 kg and body height 166.2 ± 6.7 cm). Each swimmer performed three attempts for both start techniques. The best attempt of the grab start and the track start was taken for further analysis. The following kinematic parameters were analysed: flight distance, flight time, flight velocity, entry angle and reaction time. The males had greater numeric values for the results in all kinematic parameters for the grab start compared with the track start, except for flight velocity and entry angle (flight time 0.42 vs. 0.41 s, flight distance 3.21 vs. 3.14 m, flight velocity 7.76 vs. 7.83 m/s, entry angle 44.22 vs. 43.85 degrees and reaction time 0.86 vs. 0.81 s). The females also had greater numeric values for the results in all kinematic parameters for the grab start compared with the track start, except for flight time (flight time 0.38 vs. 0.38 s, flight distance 2.82 vs. 2.73 m, flight velocity 7.47 vs. 7.31 m/s, entry angle 45.18 vs. 44.79 degrees and reaction time 0.88 vs. 0.82 s). These results indicate that the males had significantly better results for flight time and flight distance compared with the females for the grab start (flight time 0.42 vs. 0.38 s, flight distance 3.21 vs. 2.82 m). In the case of the track start, the males had significantly better results for flight distance (3.14 vs. 2.73 m). Exploring the characteristics of the two starts did not lead to any significant kinematic differences. Therefore, a conclusion that demonstrates the superiority of one of the techniques cannot be reached. The coach, together with each swimmer individually, should devote some time to decide after some tests what type of start is better for the body type and general qualifications of the swimmer.

The effect of aquatic intervention on the gross motor function and aquatic skills in children with cerebral palsy.

The objective of this study was to investigate the effect of an aquatic intervention on the gross motor function and aquatic skills of children with cerebral palsy (CP). Twenty-nine children with CP, aged 5 to 14, were recruited. Fourteen children completed an aquatic intervention (EG), and 13 children served as controls (CG). Two participants dropped out due to events (illness) unrelated to the intervention. The aquatic intervention lasted 6 weeks (2 sessions per week at 55 minutes per session) with a follow-up period of 3 weeks. The outcome measures were the Gross Motor Function Measure (GMFM) for motor function and the Water Orientation Test Alyn 2 (WOTA 2) for aquatic skills assessment. A significant improvement was observed in the secondary assessment of GMFM and WOTA 2. In contrast to the aquatic skills improvement, the GMFM change was not maintained at follow-up. Our results indicate that children with CP can improve gross motor function on dry land and aquatic skills with a 6-week water intervention. The intervention period was too short for sustainable improvement in dry-land motor skills after intervention (follow-up), but time was sufficient to achieve sustainable improvements in aquatic skills.

Functional abilities as a predictor of specific motor skills of young water polo players.

The purpose of this study was to assess the influence of functional abilities on specificmotor skills. A total number of 92 male water polo players (age 12±0.5 years, body height 156.96±22.3 cm, body weight 51.02±33.18 kg) with at least two years' experience, were enrolled in the study. The investigation protocol consisted of standardized anthropometric measurements, estimation of maximum oxygen uptake, determination of the lung function values, specific swim tests and swim tests with a ball. The factor analysis was used for the estimation of the structure of specific motor skills. The influence of functional abilities on specific motor skills was estimated by regression analysis. Out of 15 correlations in total between the variables of space of functional abilities of water polo players, 6 were significant at the level of 95% (between the variables of aerobic power and lung function) and all of the correlations (15) between the variables of specific motor skills in water polo players were significant at the 99% level. Only one principal component, the General factor of specific motor skills in water polo (GFSWP) was obtained by way of factorization of the tests of specific motor skills, so the GFSWP represents the latent space of specific motor skills as a criterion. The regression analysis showed that functional abilities (as group predictors) (p= 0.00) and forced expiratory volume in 1 second (as a separate variable) have a significant influence on GFSWP (the criterion). The results of the study pointed out the impact of functional abilities on specific motor skills of selected young water polo players. This may be important for the selection and effective coaching in the early period of training and can affect the development of more appropriate and specific training programmes for optimal physical fitness preparation in young water polo players.