For reference, 180 deg indicated full knee extension and normal standing position, respectively. The ankle in a neutral position was equal to 90 deg (angles 0�C90 deg indicated dorsiflexion selleck bio and angles 90�C180 deg indicated plantarflexion). The raw EMG data were low-pass filtered at 500 Hz and high-pass filtered at 10 Hz to eliminate movement artefacts, using a Butterworth fourth-order zero-lag filter. The onset/offset time selected from starting knee extension of the swinging leg to impact the ball. After removing the signal offset, the root mean square (RMS) was estimated from raw EMG signal data using a smoothing window. In each kick, we examined the (1) maximum RMS of RF, VM and VL muscles, (2) maximum knee angular velocity (KAV), (3) maximum ankle angular velocity (AAV), (4) maximum foot velocity (FV) and (4) maximum ball velocity (BV).

Foot velocity (Vfoot) was estimated as the velocity of the center of mass of the foot, which was calculated in each frame based on ankle and toe marker data. The mechanics of collision between the foot and ball were analyzed as suggested by Lees and Nolan (1998). Particularly, the resultant ball velocity (Vball) was calculated from V foot as follows: vball = 1.23 �� vfoot + 2.72 The Pre-stretching and Post-stretching values for each protocol were averaged across days and therefore for each participant there were four values: pre- and post- static stretching and pre- and post-dynamic stretching ones. Subsequently, in each variable, the percentage differences between pre- and post- stretching protocol were calculated and compared between protocols.

Statistical Analysis A one-way analysis of variance was used to compare relative changes in each dependent variable between static and dynamic stretching. The level of significance was set at p �� 0.05. When justified, paired sample t-tests were performed to confirm significant changes within each condition. Effect sizes (ES) were calculated and are also reported. The power was �� 0.94 and the test�Cretest reliability values for the testing order of tests ICCRs (intraclass correlation reliability) were �� 0.97. Results An example of EMG raw data of RF, VL, and VM activity after different acute stretching methods is illustrated in Figure 2. The descriptive results of raw EMG and KAV data are presented in Table 2 while mean group values are presented in Figure 3.

The ANOVA showed a statistically significant higher increase in RF EMG (Figure 3) after dynamic stretching (37.50% �� 9.37%) versus a non-significant (?8.33% �� 3.89%) decrease after static stretching (p = 0.015) (ES �� AV-951 0.94). Similarly, VL EMG increased after dynamic stretching (20% �� 10.21%) but it decreased (?6.60% �� 8.77%) after static stretching (p = 0.004) (ES �� 0.98). There was also a statistically significant increase in VM EMG after dynamic stretching (12.00% �� 6.29%) as opposed to a decrease (?12.00% �� 5.

, 1994; Cavagna et al., 2011), they are regularly MG132 proteasome of submaximal intensity and are thus not discussed here. Consequently, to the best of our knowledge, the relationships between different types of locomotion forms have not been investigated. From our point of view, it is crucial to find out whether those performances have specific qualities that should be tested and trained specifically, or whether we should observe a ��universal�� linear speed quality, regardless to different locomotion forms and movement specifics (forward, backward, lateral, bipedal, quadrupedal, etc.). This issue is particularly important in tactical activities, such as physically trained military, law enforcement, fire and rescue, protective services, and other emergency services for which those abilities are highly relevant (Faff and Korneta, 2000; Sekulic et al.

, 2006b). Thus, the purpose of our study was to determine the interrelationships between various linear maximal short-distance performances, that consist of different movement patterns (running, lateral shuffle [running], backward running and three types of specific quadrupedal locomotion). We hypothesized that there are no strong relationships between very different forms of maximal locomotion irrespectively of their similar physiological background (i.e. ATP-CP energetic requirements). Material and Methods Participants Forty-two healthy male physical education students (mean �� SD: age: 19.8 �� 1.3 years; body mass: 80.4 �� 9.6 kg; body height, 1.84 �� 0.07 m) participated in the present study.

The participants had various sports backgrounds, which included team sports (soccer, handball, basketball), racquet sports, combat sports and dance sports. All of the subjects were involved in systematic sports training for at least five years. To avoid the possible negative effect of fatigue on the test procedure, the subjects were requested not to perform strenuous exercises 48 hours prior to testing and between the testing sessions. Measures The variables in this study included six diverse linear short-distance performances of maximal intensity (three bipedal and three quadrupedal locomotions). Our objective was to obtain a similar physiological background for all of the tests. Therefore, all six tests were maximal with regard to their intensity and brevity (4�C10 s), and the straight-line distances were 18 and 30 m depending on the movement efficacy of the locomotion form.

Because of the higher movement-efficacy, the forward and backward running tests were performed over the longer distances in comparison to other tests. The subjects executed maximal performance AV-951 without a signal to avoid the possible effects of reaction time of final achievement. The subjects performed three trials of each test (from a stationary start), with at least 3 min of rest between all trials and tests. The best performance was used for further analysis.

Table 2 also shows the data relative to the velocity and space travelled in the vertical components of the CM��s movement at the moment of the ball��s release (VZ-REL and eZ-REL, respectively) as well as 100 ms before the release (VZ-100 and eZ-100, respectively). The measures selleck catalog of central tendency on the goalkeepers�� vertical movements show statistically significant differences between expert and inexperienced subjects (F(1, 68) = 4.96, p = 0.03). During the anticipation period, the experts demonstrated a clear tendency to lower their CM with a slower velocity than did their counterparts (VZ-REL) (?0.16 �� 0.21 and ?0.32 �� 0.33, respectively) and therefore moved a shorter distance at the moment of the ball��s release (ez-REL) (?0.03 �� 0.045m and ?0.055 �� 0.085m, respectively).

This lesser vertical movement of the CM in expert goalkeepers is substantiated by the values recorded for maximum vertical velocity during the anticipation phase (VZ-MAX), which was less for expert players than for inexperienced ones (?0.16 �� 0.22 m/s and ?0.24 �� 0.42 m/s, respectively). Moreover, the spatial data as well as the data on velocity components show less dispersion in expert goalkeepers. Discussion and conclusions As might be expected, the differences in the performance of both test groups confirm that the elite goalkeepers were efficient at gathering and interpreting information during the anticipation period, which was subsequently used to determine a precise intercepting movement with a higher percentage of success.

However, the inexperienced goalkeepers intercepted fewer throws, found it difficult to anticipate and identify the path of the throws, and more frequently moved in incorrect directions. When they moved in correct directions, they lacked sufficient precision. These results coincide with those of Ca?al-Bruland et al. (2010) and Vignais et al. (2009), who state that the ability to intercept a ball comes from precise technical execution, specifically of arm movements, and the ability to perceive cues up to the moment the ball leaves the player��s hand. The data gathered from the start of the goalkeepers�� movements, (TSTART-X) corroborate the studies of Savelsbergh et al. (2002, 2005) in which elite goalkeepers tended to begin movement before the thrower released the ball. The minor temporal difference in elite and inexperienced goalkeepers supports the study by Vignais et al.

(2009) reporting a similar response time between groups with varying experience levels. Nonetheless, the statistical values for the start of lateral movement, (TSTART-X), are lower than those of Savelsbergh et al. (2002), who measured 230 ms for soccer goalkeeper using a joystick. These differences could be attributed to the GSK-3 different movement structures analyzed: in our study, a complex body movement to intercept a ball, and a simple joystick movement in Savelsbergh et al. (2002).

2c). Four seconds after the initial MVC, PT was 62.6 �� 10.8 Nm, a 45 �� 13% increase compared to the pre-MVC value (Figure 2a). There was a sharp decline in PT in the following 60 s so that PT after 2 min was not selleck chemicals Pacritinib significantly different (p>0.05) from the pre-MVC PT (Figure 2a). However, PT returned to baseline pre-MVC value only after 6 min. Figure 2 Time decay of PT (a), RTD & CT (b), and RR & ?RT (c) after a 5 s MVC in response to electrical stimulation reported as % change from unpotentiated values for study 1. * p< 0.05 for unpotentiated values. PT, peak twitch ... RTD and RR increased significantly (p<0.05) by 53 �� 13% and 50 �� 17%, respectively, immediately after the MVC whilst CT and ?RT were unchanged for the duration of the experiment (Figures 2b and and2c).2c).

RTD and RR returned to the pre-MVC values within 3 min after the initial MVC. The decay in PT was associated with a progressive fall in the RTD and in the RR (Figures 2b and and2c).2c). Correlation between PT vs RTD, PT vs RR and PT vs CT was r2 = 0.99 (p<0.001), 0.98 (p<0.001) and 0.56 (p<0.01), respectively, during the 10 min period after the MVC. EMD did not change at any time during this section of the experiment (data not shown). Study 2 Unpotentiated muscle: Torque response to repeated SS over 1 min SS torque response to the first 6 episodes of electrical stimulation (Figure 1c) delivered to the unpotentiated muscle in the min prior to the first MVC did not differ from each other (p>0.05) and the mean values did not differ from those of study 1. Mean values for PT, EMD, CT, ?RT, RTD and RR were respectively 43.

5 �� 12.9 Nm, 34.2 �� 3.1 ms, 85.9 �� 9.5 ms, 80.3 �� 10.5 ms, 0.52 �� 0.18 Nm/ms and 0.56 �� 0.21 Nm/ms (Table 2). Table 2 Responses of single stimulus at specific time points at rest for study 2 (n= 6) Potentiated muscle: Torque response to repeated SS after 10 MVCs PT immediately (4 s) after the first MVC (MVC 1) was increased by 56 �� 10% (Figure 3a) to 67.0 �� 17.7 Nm. PT immediately after MVCs 2�C10 was not different (p>0.05) from PT immediately after MVC 1 (Figure 3a). Figure 3 Time decay of PT (a), RTD & CT (b) and RR & ?RT (c) after a 5 s MVC in response to electrical stimulation reported as % change from unpotentiated values for study 2. * p< 0.05 from MVC 1. Other values were not different ... PT then decayed from 4�C45 s after each MVC so that at 16 s after MVC 1, PT fell significantly (p<0.

001) from the 4 s value PT, but PT was still 29 �� 7% above the unpotentiated value after 45 s. Interestingly the following MVCs showed similar PT at 4 s after MVC, but PT was significantly (p<0.05) higher 30 and 45 s after MVC 2 and 8, 12, 16, 30 and 45 s after MVC 5 and 10 compared to MVC 1, indicating a slower decay AV-951 of PT (Figure 3a). In addition PT at 45 s after the first MVC was significantly lower (p<0.05) than were the values 45 s after any of the following MVCs (2�C10).