6.0 software package was employed for the analysis of the results. Spearman��s selleck inhibitor rank correlation coefficient and Mann-Whitney U-test were also used during the study. Results Table 2 presents the values of coefficients that determine the fight. Table 2 Characteristics of the indexes that determine activity, effectiveness and the rank of study participants (n=10) The analysis of the activity index (WA) revealed that contestants performed from 1.0 to 3.5 technical actions per fight, but a comparison of the activity within the individual periods of competition revealed a considerable difference. The studied group included both judokas whose activity increased in the second part of fight (minimum value of RWA =?1.7) and those who performed fewer actions (maximum value of RWA=0.5). The mean RWA (?0.
5) suggests a tendency for increased activity in the second part of fight. The mean value of the effectiveness index (WS) in the studied group amounted to 3.4. Similarly to the activity index, individual judokas varied considerably (minimum = 2.4 points, maximum = 6.8 points). The analysis of the RWS value (0.8 points) revealed a tendency towards a decline in the mean value of the points given in the second part of the fight. However, in individual cases, contestants demonstrated a considerable rise in effectiveness (?3.2) in the 3rd and 4th minutes of match. Although differentiation occurred, on average, the level of achievement (PO) was 3.3 with the lowest participant at 1 point and the highest participant at 6 points. Individual cases reveal that the biggest differentiation amongst the judokas was observed in movement (test No.
17, V=75.9), spatial orientation (test No. 25, V=73.4) and visual-motor coordination, (test No. 23, V=69.3). Reaction time varied the least among the group as follows: minimum reaction time to visual stimulus (test No. 3, V=6.7), mean reaction time to visual stimulus, minimum reaction time to auditory stimulus (tests No. 4 and 6, V=8.7) and also minimum reaction time and mean complex reaction time (tests No. 9 and 10, V=9.6). Table 4 compares statistically significant values of Spearman��s rank correlation coefficients calculated between the results of coordination tests and the sports performance in the studied group of contestants. Table 4 Statistically significant (p<0.
05) values of rank correlation coefficient calculated between the results of coordination tests and sports performance in the studied group of contestants. (n=10) Analysis of the value of Spearman��s R coefficient for WA revealed that its value was negatively correlated to the ability to differentiate movements (high correlation, Spearman��s coefficient: R=?0,7). While the examination of WA1 (activity index for the first part Dacomitinib of match) revealed a positive correlation to mean reaction time (Spearman��s R coefficient=0.65) and maximum reaction time (Spearman��s R coefficient=0.
(2000) regarding the concept of exercise intensity. They stated that contrary to the classical thought which had defined exercise intensity as the magnitude of the load employed, research use only it must have been defined as the rate of the work performed. In the 1st and 6th phases, E30 and E0 generated significantly less EMG activity compared with NM (Figure 4). This result could be attributed to the necessity of less muscle effort to overcome the inertia of much lower external load in ER exercises during the early concentric and late eccentric phases of contraction. Nonetheless, the findings of the present study highlighted the effect of reducing the initial length of elastic material in achieving significantly higher muscle activation and applied lead by elastic resistance device (Figures 2 and and4).4).
The data demonstrated dramatically higher EMG values for E30 compared with E0 in all phases of contraction, except in the 3rd phase in which equal EMG readings was observed between the two modes of training. Based on similar finding, Hodges (2006) concluded that after reducing the initial length of elastic material, a shifting occurs in the distribution of muscle tension from late concentric to early concentric and from early eccentric to late eccentric range of motion. Accordingly, E30 exhibited significantly higher EMG than E0 in the 1st (48%) and the 6th (84.31%) phases. These data disclose the importance of reducing the initial length as an essential strategy to develop muscle activation by ER devices. Conclusion Many athletes rather use various modalities of resistance exercise (e.
g. free weights, pulley machines, isokinetic dynamometers, elastic resistance, etc) within their conditioning program with the prevailing view that each type of strength training offers a unique mechanical and physiological muscle stimulation (Welsch et al., 2005). On this basis, undertaking several types of resistance exercise might facilitate better development of the muscle performance. Based on equal average EMG between E30 and NM, the findings of the present study suggest that E30 could be an alternative to the use of NM in high exercise intensity (8-RM). However, since NM displayed higher EMG compared with E30 in the early concentric and late eccentric phases and E30 demonstrated higher muscle activation in the late concentric and early eccentric phases of contraction, a training protocol comprised of both modes of exercise seems to be ideal.
Acknowledgments For this investigation a research grant was provided by University of Malaya, Malaysia (PS008/2008C).
During the last 50 years, muscle strength training (ST) has been a major topic for coaches, athletes and researchers (Marques and Gonz��lez-Badillo, 2006). However, despite GSK-3 increasing professionalization, there is a paucity of research data concerning performance in elite athletes. Two main reasons for this may be suggested.
The average power with the full squat with 70kg also showed significant positive correlations with the sprint times. The CMJ height has been greatly used to access lower body power in soccer players (Wisloff, 1998; Helgerud, 2001; N��?ez, 2008; Ronnestad, 2008). Nevertheless, to our knowledge, only two previous studies done (Gorostiaga, 2004; L��pez-Segovia, 2010) have used loaded countermovement jump (CMJL) exercise for testing lower limb power in this population. Unfortunately, these authors (Gorostiaga, 2004; L��pez-Segovia, 2010) did not include sprint evaluations in their studies. Different factors such as lower reliability of testing at very short distances, the static start position in the sprint test and the location of the first photoelectric cells (30 cm behind start in these two studies) could explain the lack relationship reported between CMJ and time at 10m.
Although, the relationship obtained between the vertical jump and 30m sprint time (present study: r= ?0.55; p<0.05 vs. r= ?0.60; p<0.01) was similar to the study of Wisloff (2004), the relationships observed between the vertical jump and last running meters are consistent with the results perceived with loaded jump, given a similarity of muscle action in both types of jumps. Significant association between peak power during loaded CMJ and later stages of the sprint (r=?0.544 to ?0.611; p��0.05) were obtained. The T10�C30 and T20�C30 were significantly related with peak power observed in the CMJL exercise with 20, 30, and 40kg external load.
Cronin and Hansen (2005) observed similar results in professional rugby players between loaded (30kg) vertical jump height and 5m, 10m, and 15m sprint times. The higher relationships (R2= 41�C62%) observed in the present study were perceived with the longer distances rather than the initial run. As running velocity approaches maximum, those strength measures that require force to be produced at high velocities have been reported to be significantly related to sprint performance (Wilson, 1995; Young, 1995; Nesser, 1996). Wilson (1995) reported a significant relationship between force at 30 ms in a concentric squat jump and 30m sprint time (r= 0.62). Nesser (1996) claimed significant correlations between 40m sprint time and peak isokinetic torque at a velocity of 7.85 rad/s for the hip and knee extensors and knee flexors (r= 0.54 to 0.61).
We agree with the assertion that results show a slight tendency of increased relationships such as velocity and distance increased (Table 2). Moreover, data showed that power output during the vertical jump with 20kg best explained sprint performance. This parameter was also significantly correlated with all split speed measurements, including the first sprint stages. Although correlations do not signify causation, CMJ training with light loads could be important Batimastat to improve sprint performance in soccer player��s under-21.
Moreover, these cells quality control are available in virtually all post-natal tissues. There, they occupy a perivascular niche to support and maintain different connective and skeletal tissues.22 This fact makes very probable that other new sources may come up in the future since MSCs obtained from different places show close phenotypic characteristics. However, it is still unclear whether we may be dealing with the same MSCs or not because proliferation and differentiation capabilities in the presence of different growth factor stimulus do differ depending on the source of origin. For instance, bone marrow mesenchymal stem cells (BM-MSCs) have a tendency to loose their proliferative potential with age and it is notorious the lost of differentiation capabilities after age 20.
23 On the contrary, it has been shown that mesenchymal stem cells from the dental pulp (DPSCs) have higher proliferation index and growth potential even though both stem cell populations (BM-MSCs and DPSCs) still express very close surface markers such as Stro-1, CD44, 3G5, CD146 and CD106.23 As a matter of fact, Wagner et al24 performed a gene expression profile study of MSCs coming from different origins (bone marrow, adipose tissue and cord blood) and compared them to HS68 fibroblasts. They showed that, though MSCs coming from different donors and exposed to the same culture conditions gave rise to a stable and reproducible gene expression profile, MSCs from different sources or cultured with different procedures differentially expressed many genes.
On the contrary, no differences were found in a subset of 22 surface antigen markers suggesting that MSCs from different origin may share common phenotypic and receptor expression but indeed, they seem to be distinct at the genetic level. Peculiar differences are also seen in their differentiation potential where certain MSCs have been reported to show either tendencies or difficulties to differentiate into specific cellular lineages. For instance, DPSCs predominantly differentiate into bone and neurons25,26 and it has already been described unsuccessful trials for adipogenic differentiation in umbilical cord mesenchymal stem cells (UC-MSCs).27 Taking all these facts together we may conclude that even general biological characteristics of MSCs coming from different sources are common and comparable, major differences come up in terms of expansion and differentiation potential which should be taken under consideration before future clinical and therapeutic approaches.
THE DENTAL PULP STEM CELL NICHE After injury, the dental pulp (Figure 3) plays a major role in tooth regeneration by participating in a process called reparative dentinogenesis, where cells create and accumulate new dentin matrix to repair Carfilzomib the damaged area.28 Bigger traumas or advanced caries, for instance, can eventually cause the death of the pre-existing population of odontoblast.
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 www.selleckchem.com/products/XL184.html 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 Dacomitinib 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).
41 points) following high intensity exercise (90% of RM). All parameters of the study, grip strength and passing accuracy showed a significant decrease selleck catalog (p<0.05). Figure 3 shows the differences between pre and post measurements for the group 2. After applying the fatigue protocols the researcher compared between the two experimental groups in post-test for grip strength and passing accuracy by using post-test mean, standard deviations (SD) and significant differences. Table 3 shows a significant difference in the post measurements between the two experimental groups. The results showed no significant difference (p>0.05) in the performance between both groups regarding the grip strength and passing accuracy following fatigue protocols at exercise intensity (70% of 1 RM), and fatigue protocols at exercise intensity (90% of 1 RM).
Figure 3 Differences between pre and post measurements for group 2. Table 2 Means, standard deviations (SD) and significant differences between pre and post measurement for group (2) on handgrip strength and passing accuracy. Table 3 Means, standard deviations (SD) and significant differences in the post measurement between experimental groups on handgrip strength and passing accuracy. Discussion The present study was conducted to investigate the effect of upper extremity fatigue on grip strength and passing accuracy in basketball, and to ascertain if the effects of different fatigue protocols on grip strength and passing accuracy are similar. The results from this study showed that there were significant differences (p<0.
05) in the performance between pre-test, post-test for group 1 which used the dumbbell chest press as a fatigue protocol. The paired samples t-test was used to examine the mean difference in the performance at rest and the performance under the influence of exercise intensity of 70% of RM in the dominant hand grip, non-dominant hand grip and passing accuracy for group 1. It showed that there was a significant difference (p<0.05) in the results between the performance at rest and the performance following moderate intensity exercise. The same t-test was used to examine the mean difference in the performance at rest and the performance under the influence of exercise at intensity of 90% of RM, in the dominant hand grip, non-dominant hand grip and passing accuracy. The results showed that there was a significant difference (p<0.
05) in the performance Dacomitinib between the performance at rest and that following high intensity exercise. Figure 2 shows that there was a clear deterioration in the performance for group 1, which used the dumbbell chest press fatigue protocols. The paired samples t-test was used to examine the rate of decline or the change in the dominant hand grip, non-dominant hand grip and passing accuracy for group 2 from the rest to exercise of intensity 70% of RM. Results showed that there was a significant difference (p<0.