103,353 research outputs found
Skin temperature modifications during physical exercise measured by infrared thermography
No full textHeat dissipation during sport exercise is an important physiological mechanism that may affect athletic performance. It depends on skin temperature (ST) and on cutaneous blood flow (CBF). ST, as an indicator of CBF, can be measured by infrared thermography (IRT). ST modifications during different kinds of exercise have been studied by few researchers using IRT.
Global endurance exercise, such as graded load running, was characterized by a decrease in the ST of the all body (Merla et al., 2010); similar results was also found in incremental cycling exercise where the ST of the trunk (Torii et al., 1992) and of the finger of the hand (Zontak et al., 1998) begun to fall immediately on starting to exercise.
Different ST trend was found in exercise involving only small muscle groups. In a localized resistance physical exercise it was observed a little increase in ST of the posterior thigh (Ferreira et al., 2008) and of the deltoid after static exertion until exhaustion (Bertmaring et al., 2008).
Also breathing exercises were evaluated using IRT: it was found a different dynamics of ST changes in diaphragmatic and thoracic respiration. In diaphragmatic exercise, which mainly uses internal musculature, as compared to thoracic one, temperature did not increase in trunk areas. This is probably due to a lesser use of superficial muscle (Ludwig et al., 2012).
A recent study put in evidence that trained subjects responded more quickly than untrained controls in standing calf raise exercise (Formenti et al., 2013). A possible explanation may be found in the different grade of vasoconstriction in trained and untrained subjects that occur in the beginning of the exercise.
In a new study that we are performing, we would to test the hypothesis that differences in ST trend exist in two modalities of squat exercise: normal velocity of movement (1 sec. eccentric/1 sec. concentric phase) and slow velocity of movement (5 sec. eccentric/5 sec. concentric phase) that should cause more vasoconstriction in the quadriceps.
Medical thermal images are captured in several modes that can be classified according to the temporal rate of shooting. Single state image enhance areas of the body with hot and cold spots. Temporal sequences of thermal images can be helpful to detect thermal anomalies linked to different pathologies and during exercise. With very fast image shooting (100 hz.) it is possible to detect variations in temperature arise from hemodynamic or neural control. Because of the difficult in recording and analyzing thermal images, the methods by researchers are not similar with the others. Thus, further studies are necessary to standardize the methods both in thermal images analysis and protocol procedure, as well as applying IRT to other kind of physical exercises and subjects.
Bibliography
Bertmaring et al., Ergonomics. 2008, 51, 1606-1619.
Ferreira et al., Ann. Biomed. Eng. 2008, 37, 1420-1427.
Formenti et al., Ann. Biomed. Eng. 2013, 41, 863-871.
Ludwig et al., Acta Bioeng. Biomech. 2012, 14, 41-47.
Merla et al., Ann. Biomed. Eng. 2010, 38, 158-63.
Torii et al., Br. J. Sports. Med. 1992, 26, 29-32.
Zontak et al., Ann. Biomed. Eng. 1998, 26, 988-993
Intravideo. Arte elettronica e Avanguardia
No full textHanno preso parte alle giornate di studio: A. Abruzzese, S. Bordini, M.M. Gazzano, S. Lischi, I. Pezzini, P. Vinci, G. De Vincenti, B. Di Marino, V. Valentini.
Artisti invitati: Robert Cahen, Studio Azzurro, Gianfranco Baruchello
Effects of three different training programmes on instep kick in preadolescent football players
No full textIntroduction
The Instep Kick (IK) is a basic element of a soccer game. It is a multi-joint activity affected by numerous factors, such as strength and power of the muscles involved in the kick (2), movement timing and stretch-shortening cycle among segments that contribute in the kick (3), and approach of the player to the ball (3).
The purpose of this study was to investigate the effects of specific (instep kick), non-specific (i.e., small side game and condition training) training on the speed of the ball in an IK on dominant and non-dominant legs in preadolescent Italian football players.
Methods
Eighteen male football players (age: 11 y, height: 1.45±0.09 m, weight: 36.9±6.0 kg) were recruited from an amateur Italian football team. Participants followed 6-weeks of specific training, in addition of their baseline football training and were randomly divided into three groups: 1) Instep Kick Group (IKG, n=6); 2) Conditional Group (CG, n=6) and 3) Small Side Games Group (SSG, n=6).
In all the training sessions (twice per week), IKG performed 20 IK (using maximum force) into the goal with dominant and non-dominant legs; CG performed four different conditional football exercises (i.e., 10 sets of the T-drill, 10 sets of 4 consecutives alternate bipodalic lateral jumps, 8 series of 5 consecutive bipodalic frontal jumps, 10 series of the stop-and-start drill); and SSG performed 20 minutes of 3 vs 3 small side game.
The football players were tested pre and post training periods on the speed of the ball in an IK on dominant and non-dominant legs. In each day test, participants performed four kicks with the left and the right leg and the speed of the ball was recorded using a speed radar gun (model#10-1925, Bushnell Outdoor Products, Overland Park, KS, USA). Among the 4 kicks, the higher speed recorded was used in the statistical analysis.
Two-way analysis of variance with repeated measures on one factor was used in order to detect differences among the three groups and between pre and post training period, in the dominant and non-dominant legs separately. Least Significant Difference test (LSD) was used as post-hoc analysis.
Results
Significant improvement in IK of about 5.7% was found in each group between pre and post training periods in dominant leg (Within-subjects difference: F(1,15)=21.805, p<0.001). Significant interaction was found in non-dominant leg (Interaction: F(2,15)=21.805, p=0.001). The LSD post-hoc test showed statistical improvement only in IKG of 10.3% between pre and post training period (p=0.002).
Conclusion
The three different trainings produced the same improvement on the speed of the ball in an IK on dominant leg. Conversely, on non-dominant leg it was found different effects between training methods. In particular, the IKG obtained larger improvement than the CG and SSG on non-dominant leg.
The young football players often use the dominant leg to manipulate the ball (1), and for this reasons the dominant leg did not require any specific training to improve the speed of the ball in an IK. For the same reason, the 11 years old football players obtained larger improvement on non-dominant leg, probably because trained to repeat the IK numerous times.
References
1. Bjelica D, Popovic S, Petkovic J. Comparison of instep kicking between preferred and non-preferred leg in young football players. Monten J Sports Sci Med 2013; 2: 5-10
2. Dörge HC, Andersen T B, Sørensen H, Simonsen EB, Aagaard H, Dyhre-Poulsen P, Klausen K. EMG activity of the iliopsoas muscle and leg kinetics during the soccer place kick. Scand J Med Sci Sports 1999; 9: 195-200
3. Kapidžić A, Huremović T, Biberovic A. Kinematic analysis of the instep kick in youth soccer players. J Hum Kinet 2014; 42: 81-9
SOMATOSENSORY TRANSMISSION THROUGH THE VENTROPOSTEROLATERAL THALAMIC NUCLEUS DURING SLEEP AND WAKEFULNESS
No full textSomatovariants of Sardinian recruits from the three principal geographic areas of the island.
No full textSystematic implementation of laparoscopic hysterectomy independent of uterus size: clinical effect.
No full textTo investigate the effect of uterine weight on the mode of hysterectomy and on perioperative outcomes and to explore how the increasing experience in endoscopic techniques influenced our choice of surgical approach to hysterectomy to treat benign conditions.Retrospective analysis (Canadian Task Force classification II-2).University-based department of obstetrics and gynecology.A series of 1518 consecutive women with benign uterine conditions other than pelvic organ prolapse who underwent hysterectomy at our department between January 2000 and December 2011.Gradual implementation of the laparoscopic approach over years, with the goal of attempting endoscopic hysterectomy whenever possible and irrespective of uterine weight. Comparisons were made on the basis of various approaches to hysterectomy including vaginal hysterectomy (VH), abdominal hysterectomy (AH), and total laparoscopic hysterectomy (TLH) and on uterine weight.Hysterectomies performed included 568 VH (37.4\%), 234 AH (15.4\%), and 716 TLH (47.2\%). Postoperative complications were lower in the TLH group vs the AH group; no significant difference was observed between the VH vs TLH groups or the AH vs VH groups. A marked reduction in the need for open surgery was noted between 2000 and 2011 (p for trend <.001). Restricting the analysis to TLH, an increase in operative time and blood loss was observed, parallel to increasing uterine weight. Hospital stay and rate of intraoperative and postoperative complications were independent of uterine weight. In 45 women with uterus weight ≥1000 g, the initial approach was via laparoscopy, with a success rate of 95.6\% (n = 43). A marked tendency toward reduction in the use of open surgery was observed through the years when uterine weight was ≥1 kg (p for trend <.001).Systematic implementation of laparoscopic hysterectomy enables a marked reduction in the need for AH. In experienced hands, even very large uteri (≥1 kg) can be safely removed via laparoscopy
First data on the nuclear DNA content (Feulgen-positive material) of Perodicticus potto
No full textThe nuclear DNA content (Feulgen-positive material) of Perodicticus potto, measured on lymphocytes from six animals of the subspecies edwarsi (Gabon) and potto (Dahomey and Liberia) is quite homogeneous around a mean value of 6·87 ± 0·15 pg. A difference of 1·5% has been found between sexes in each subspecies; the possible relation of this fact to the characteristics of the karyotype is discussed
The influence of knee joint angle and time of force application on vertical jump height during volleyball commit-block
No full textIntroduction: Blocking successfully is a crucial feature of winning in volleyball. Key points for the effectiveness of block are anticipation, decision-making, movement speed and jumping ability (Lobietti, 2009). It was found that jumping from a position with knees more flexed seems to be the best strategy to achieve the best performance (Gheller et al., 2015). However, during volleyball commit-block (VCB) the time spent during deeper squat could negatively affect the efficacy of the VCB (Ficklin et al., 2014). Thus, we aimed to investigate the influence of three different knee starting angles and the time of force application on jumping performance during VCB. Methods: Fifteen volleyball players were recruited (20.27±3.08 yrs, 76.60±9.27 kg, 184.53±6.63 cm). Players performed three maximal vertical jumps in commit position in front of the volleyball net. In the first one the players performed jumps using their optimal knee joint angle (OR) (105.91±14.80 deg). The second one was performed over their optimal one (OOR) (71.13±18.13 deg) and third one under the optimal one (UOR) (135.94±7.95 deg). The vertical jump height (VJH) and the time of force application (TFA) were obtained by Optojump Next (Microgate, Italy). The knee joint angle (KJA) was assessed using Microsoft KinectTM. One-way MANOVA corrected by GreenHouse-Geisser adjustment was used to detect differences among jumps in VJH, TFA, and KJA. The magnitude of the difference was assessed by partial eta squared (part 2). LSD was performed in accordance to univariate ANOVA. Results The MANOVA showed statistical difference among the three jumps (F(6,9)=53.273, p<0.001, part 2=0.973). The univariate test detected difference among the independent variable in each dependent variable (VJH: F(1.93,27)=30.601, p<0.001, part 2=0.686; TFA: F(1.96,27.49)=112.196, p<0.001, part 2=0.889; KJA: F(1.807,25.303)=114.864, p<0.001, part 2=0.891). In VJH, difference between OR and UOR (p<0.001) was detected by LSD but no statistical difference was found between OR and OOR (p=0.956). In TFA and KJA, statistical differences were found by LSD in each pairwise comparisons (p<0.001). Discussion: In contrast to Gheller et al. (2015), no difference was found in VJH, even if both TFA and KJA were different between OR and OOR. Thus, jumping at the preferred range should be the best way to reach successful VCB because of higher vertical jump performance applying shorter TFA than OOR. References: Ficklin T, Lund R, Schipper M. (2014). J Sports Sci Med, 13(1), 78. Gheller RG, Dal Pupo J, Ache-Dias J, Detanico D, Padulo J, Dos Santos SG. (2015). Hum Mov Sci, 42, 71–80. Lobietti R. (2009). J Hum Sport Exerc, 4(2), 93–99
Somatovariants of Sardinian recruits from the three principal geographic areas of the island
No full textUsing the constitutional method based on somatovariants, three samples with a total of 1207 recruits, divided according to the three main geographic areas of Sardinia (North, Center, South) were compared. Individuals from the center of the island are lighter and shorter than those belonging to the other two regions. Since this somatic typology corresponds to expectations based on data analyzed in a previous investigation, the somatotype method can be considered to be a valuable instrument for quick, preliminary constitutional typings
Resistance training with slow movement in wing chung martial artists
No full textExhaustion (RTSM) in Wing Chun martial artists. It has been demonstrated that the ballistic training increases the movement velocity but
decreases the force; in opposite the conventional resistance training increases the force but not the movement velocity (Olsen P.D., et al.
2003). Blood flow restriction resistance training with slow velocity of muscle action, without elastic cuff, performed with low load intensity,
is considered an efficacy training method for improving muscular function (Alberti G., et al. 2013). Using resistance training in addition to
standard ballistic training, may be a useful strategy for improving muscular function in martial artists. Methods 22 Wing Chun martial
artists (31.82±11.17 yrs; 23.64±2.14 kg/m2) were randomly divided in 2 groups: experimental group (EG) performed 4 weeks, with 3 sessions
per week, of RTSM (5s concentric and 5s eccentric) with 50% of 1RM in addition to the baseline training, whereas the control group
(CG) continued their baseline training. Before and after the intervention, the subjects were tested on: 1 maximal repetition on bench press
(1RM), peak power during bench press (PP) by using Kinovea (Balsalobre-Fernandez C., et al. 2014), and maximum punch repetition in 5s
(MP5). To investigate within and between groups effect of the training intervention on these parameters, paired and unpaired t-test were
performed. Results Significant difference was not found between the 2 groups before the training period. The EG improved PP (p<0.001;ES=0.63, moderate) and 1RM (p<0.001; ES=0.53, moderate), while the EG did not improve any parameters from pre to post training period.
In the post test we found a significant difference between CG and EG only in 1RM (p<0.05; ES=1.11, very large). However the MP5 did
not change from pre to post training in both groups. Discussion The higher values of EG in PP and 1RM in the post training showed that
RTSM could be an efficient training method for improving general muscular function. Moreover, MP5 in EG did not decrease from pre to
post training; this is probably due to the high specificity and the high neuromuscular demand of the punching technique (VencesBrito M.,
et al. 2011). These considerations demonstrate that such low intensity resistance method can be considered part of the routine training of
Wing Chun martial artists. Reference Alberti G., et al. (2013) SCJ Balsalobre-Fernandez C., et al. (2014) JSCR VencesBrito M., et al. (2011) JEK
Olsen P.D., et al. (2003) JS
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