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Marina M.,INEFC Barcelona | Torrado P.,INEFC Barcelona | Busquets A.,INEFC Barcelona | Angulo-Barroso R.,INEFC Barcelona
Journal of Electromyography and Kinesiology | Year: 2013

Motorcycle races' long duration justify the study of forearm muscles fatigue, especially knowing the frequently associated forearm discomfort pathology. Moreover, while continuous fatigue protocols yield unequivocal results, EMG outcomes from an intermittent protocol are quite controversial.This study examined the forearm muscle fatigue patterns produced during these two protocols, comparing riders with a control group, and relating maximal voluntary contraction with EMG parameters (amplitude - NRMS and median frequency - NMF) of both protocols to the forearm discomfort among motorcycle riders.Twenty riders and 39 controls performed in separate days both protocols simulating the braking gesture and posture of a rider. EMG of flexor digitorum superficialis (FS) and carpi radialis (CR) were monitored.CR revealed more differences among protocols and groups compared to FS. The greater CR activation in riders could be interpreted as a neuromotor strategy to improve braking precision. When FS fatigue increased, the control group progressively shift toward a bigger CR activation, adopting an intermuscular activation pattern closer to riders. Despite the absence of NMF decrement throughout the intermittent protocol, which suggest that we should have shorten the recovery times from the actual 1. min, the superior number of rounds performed by the riders proved that this protocol discriminates better riders against controls and is more related to forearm discomfort. © 2012 Elsevier Ltd.


Marina M.,INEFC Barcelona | Torrado P.,INEFC Barcelona | Busquets A.,University Pompeu Fabra | Angulo-Barroso R.,INEFC Barcelona
Scandinavian Journal of Medicine and Science in Sports | Year: 2015

Fatigue in forearm muscles may be critical for motorcycle riders in relation to performance and forearm disorders. Force-time course parameters were examined to better characterize the reduction in the maximal force generating capacity (MVC) during an intermittent fatigue protocol (IFP) specifically designed for motorcycle riders. Also, a mathematical force fatigue model is proposed. Forty motorcyclists (aged 27.6±6.8 years) performed an IFP that simulated the braking gesture and posture of a rider. Fatigue was confirmed by a 40% decrement of the normalized MVC in comparison with basal value. Contraction time increased in comparison with basal condition (P≤0.034). Relaxation kinetics presented two phases: (a) a pre-fatigue phase where half relaxation time (HRTraw) and normalized (HRTnor) decreased (P≤0.013) while relaxation rate (RRraw) remained unchanged; and (b) a fatiguing phase where HRTraw, HRTnor increased and RRraw decreased (P≤0.047). Normalized RRraw (RRnor) declined progressively (P≤0.016). The proposed nonlinear force fatigue model confirmed a satisfactory adjustment (R2=0.977±0.018). This mathematical expression derived three patterns of force fatigue: three-phase, exponential and linear, representing 70%, 13%, and 17% of the participants, respectively. Overall, these results provided further support to force fatigue theoretical and applied proposals. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.


Marina M.,INEFC Barcelona | Jemni M.,University of Greenwich
Journal of Strength and Conditioning Research | Year: 2014

Marina, M and Jemni, M. Plyometric training performance in elite-oriented prepubertal female gymnasts. J Strength Cond Res 28(4): 1015-1025, 2014-We studied the effectiveness of a combined strength and plyometric training program (experimental period) on jumping performance when compared with a training routine on apparatus (control period) over 2 successive gymnastics training seasons. Nine female elite-orientated gymnasts (around 30-hour training per week) were participated in the study. The study was based on a 20-month longitudinal design covering 2 training seasons separated by a competitive period and transition periods. Each season included 1 control and 1 experimental period (CtrlΔ1 + ExΔ1 and CtrlΔ2 + ExΔ2, respectively). Before and after each control and experimental period, we assessed plyometric performance by means of drop jumps (DJs) from 20, 40, 60, 80, and 100 cm. The jump performance variables considered were flight time (FT), contact time (CT), flight-contact ratio (FC), and estimated mechanical power (also called Bosco expression [BE]), all of which were expressed as raw data and normalized (expressed as a percentage) with respect to the recordings at the beginning of each period of analysis. Flight time was the only variable to increase not only during both experimental periods but also during both controls. Our results confirmed larger relative increments of all the variables (FT, CT, BE, and FC), except for CT at DJs of 80 and 100 cm, during the experimental periods than during their respective previous control periods. Despite the additive effect of growth, development, and maturation, the gymnasts were not able to maintain the DJ performance accomplished during ExΔ1, thereby confirming detraining during the competitive and transition periods. We conclude that a combination of heavy resistance training with high impact plyometric jumps is effective in prepubertal gymnasts, despite their initial high level of physical conditioning. © 2014 National Strength and Conditioning Association.


Marina M.,INEFC Barcelona | Torrado P.,INEFC Barcelona
Journal of Sports Sciences | Year: 2013

The objective of this study was to confirm whether gymnastics practice from a young age can induce greater vertical jump reliability. Fifty young female gymnasts (8.84 ± 0.62 years) and 42 females in the control group (8.58 ± 0.92 years) performed the following jump tests on a contact mat: squat jump, countermovement jump, countermovement jump with arm swing and drop jump from heights of 40 and 60 cm. The two testing sessions had three trials each and were separated by one week. A 2 (groups) × 2 (sessions) × 3 (trials) repeated measures analysis of variance (ANOVA) and a test-retest correlation analysis were used to study the reliability. There was no systematic source of error in either group for nonplyometric jumps such as squat jump, countermovement jump, and countermovement jump with arm swing. A significant group per trial interaction revealed a learning effect in gymnasts' drop jumps from 40 cm height. Additionally, the test-retest correlation analysis and the higher minimum detectable error suggest that the quick drop jump technique was not fully consolidated in either group. At an introductory level of gymnastics and between the ages of 8-10 years, the condition of being a gymnast did not lead to conclusively higher reliability, aside from better overall vertical jump performance. © 2013 Taylor & Francis.


Marina M.,INEFC Barcelona | Porta J.,INEFC Barcelona | Vallejo L.,INEFC Barcelona | Angulo R.,INEFC Barcelona
Journal of Electromyography and Kinesiology | Year: 2011

Motorcycle riders must endure high levels of muscle tension for long periods of time, especially in their arms and forearms, when steering and using handlebar controls. Because the right hand operates the gas handle and front brakes, the present research focuses on fatigue in the right hand flexors. Ten adult riders, aged 32.5 ± 5.5. years, volunteered to participate in this study. During the 24. h race each rider, on completion of a relay stage, visited the assessment box to do the following handgrip test sequence: (1) 10. s of EMG recording at rest, (2) one 3-s maximal voluntary contraction (MVC), (3) 1. min rest interval and (4) 50% MVC maintained during 10. s. EMG amplitude (MP: μV) and median and mean frequency (MF and MPF: Hz) over the superficial finger flexors were recorded during the whole handgrip test sequence with adhesive surface electrodes.MVC values were maintained during the first two relays (50-60. min duration in total) and dropped gradually thereafter (p<0.01). During the monitoring of the 50% MVC, mean amplitude increased (p=0.024) while median and mean frequency tended to decrease. These results suggest fatigue is produced in motorcycle riders in a 24. h race. However, the expected reduction of EMG frequency was not confirmed given to a potentially large variability. © 2010 Elsevier Ltd.


Marina M.,INEFC Barcelona | Rodriguez F.A.,INEFC Barcelona
Biology of Sport | Year: 2014

The objective of this study was to investigate the physiological indices of competitive routines in women's artistic gymnastics by characterizing post-exercise heart rate (HR), oxygen uptake (VO2) and peak blood lactate concentration (Lmax) in a group of eight young elite-oriented female gymnasts. HR was continuously monitored with Polar RS400 monitors during the test event simulating a competition environment. Within 5 s of the end of each routine, the breath-by-breath gas analyser mask was placed on the face to record VO2. VO2max was calculated by the backward extrapolation method of the VO2 recovery curve. Lmax was obtained during recovery (min 1, 3, 5, 7 and 10) subsequent to each event. One week later, HR, VO2 and Lmax were measured during an incremental continuous treadmill test. The treadmill test was confirmed as the assessment with the highest physiological demand. The gymnasts reached their highest values of HR (183-199 beats · min-1), VO 2/Bm (33-44 ml · kg-1 · min-1) and Lmax (7-9 mmol · l-1) in the floor and uneven bars exercises. The vault was the event with the lowest HR (154-166 beats · min-1) and Lmax (2.4-2.6 mmol · l -1), and the balance beam had the lowest VO2 (27-35 ml · kg-1 · min-1). The mean relative peak intensities attained in the different events, which ranged from 65 to 85% of the individual VO2max and HRmax recorded in the laboratory, suggest that cardiorespiratory and metabolic demands are higher than previously indicated. The high percentage of VO2 measured, particularly after the floor event, suggests that aerobic power training should not be neglected in women's artistic gymnastics. Copyright © Biology of Sport 2014.


Marina M.,INEFC Barcelona | Jemni M.,University of Greenwich | Rodriguez F.A.,INEFC Barcelona | Jimenez A.,University of Greenwich
Journal of Strength and Conditioning Research | Year: 2012

The objective of this study was to investigate and compare the factors influencing plyometric jumping performance between well-trained gymnasts and a control group. Seventy-six gymnasts and 91 moderately active subjects volunteered to participate in this study. Drop jumps (DJ) were performed from 20-, 40-, 60-, 80-, and 100-cm heights. Flight time (FT) and contact time (CT) were recorded using contact mat. Flight time to contact time (FC) ratio and Bosco expression (BE) were calculated. Male gymnasts scored similar FT to their controls, whereas female gymnasts had significantly longer FT compared with their peers. The gymnasts obtained significantly shorter CT than their control groups, whereas their FC ratios were significantly higher and increased when the height of the drops was close to 60 cm. Moreover, gymnasts' BE was greater in comparison to their respective control groups independent of the drop height. The height of the drop that produced the best FC ratio and BE varied between the groups. The best performances were obtained between 40and 60-cm drop height for both groups. Female control group showed a trend toward a continuing decline with the increase of the drop height. The best gymnasts (finalists at World Championships) obtained their best performance at 80-cm drop. Flight time is the less discriminating factor distinguishing gymnasts' DJ performances. Considering CT, FC, and BE results all together could better profile the gymnasts rather than taken separately. Bosco expression was shown to be more sensitive to the increase in FT; we suggest BE as the best criteria to assess the appropriate drop height for plyometric training purposes in gymnasts as it has been significantly correlated to FT. © 2012 National Strength and Conditioning Association.


Michel M.,INEFC Barcelona | Monem J.,INEFC Barcelona | Ferran R.,INEFC Barcelona
The Journal of sports medicine and physical fitness | Year: 2014

BACKGROUND: Aim of the present study was to assess the efficacy and trainability of intensive training programs based on plyometrics and strength conditioning over two successive seasons compared to habitual routines.METHODS: Nine female gymnasts following typical elite training routines (30 h per week) volunteered for this study. They performed the following jump tests on the same day: 1) squat jump with progressive loads of 0%, 25%, 50%, 75% and 100% of body mass (SJ0-25-50-75-100); 2) counter movement jump (CMJ); and 3) counter movement jump with arm swing (CMJA). Flight time (FT), and FT with respect to body mass (FTbm) were the parameters analysed. This study was based on a 20-month longitudinal design covering two training seasons. Each season included one control and one experimental period (CtrlΔ1 + ExΔ1 and CtrlΔ2 + ExΔ2 respectively), with jump assessment at the beginning and end of each period. The gymnasts demonstrated a significantly greater improvement of jump performance during the two experimental periods than in the respective control periods.RESULTS: Results confirm the detraining phenomenon after ExΔ1 and indicate that when the girls reach a very high level of jumping performance, it is very difficult to maintain this. The contractile component (CC) improved much more during the two experimental periods than during their respective control periods. In contrast the elastic component (EC) and arm participation (AP) did not change significantly during the two-season monitoring.CONCLUSION: On the basis of our findings, we suggest that it is worthwhile to reduce the time spent on technical routines on apparatus and that 2-3 intense physical conditioning workouts be introduced to optimize gymnasts' jumping skills.


Marina M.,INEFC Barcelona | Jemni M.,University of Greenwich | Rodriguez F.,INEFC Barcelona
Journal of Sports Medicine and Physical Fitness | Year: 2013

Aim. The aim of this study was to establish a more precise jumping performance profile of elite gymnasts than that published in previous studies. Methods. Seventy-six elite male and female competitive gymnasts and 91 moderately active subjects volunteered for the study. The jumping tests performed on a contact mat were: squat jump (SJ) with progressive loads of 0%, 25%, 50%, 75% and 100% of body mass, counter-movement jump (CMJ), and counter-movement jump with arm swing (CMJA). The parameters used to assess the jumping performance were flight time (FT, ms), FT normalized to body mass (FTbm, ms/kg), estimated elastic component (EC) and arm participation (AP). In SJ, the overload with respect to body mass had a negative impact on reliability in all of the subgroups that were analysed. When overloads were above 50% of body mass in SJ, reliability was poor. Therefore, overloads should not be used with sedentary young females. Gymnasts carry out a large number of jumps from very young ages, which may explain their high jump reliability (ICC>0.91). Results. We used FT to estimate the F-v curve through SJ with overloads. The curves for male gymnasts and their controls were practically identical. However, when FT was normalized to body mass (FTbm), the F-v curve showed the advantage of female gymnasts in particular over their control group when overloads were above 50%. Larger, more significant (P<0.001) differences between gymnasts and their control groups were observed in CMJ and CMJA, with FTbminstead of FT. The combination of poor SJ and good CMJ performances explains why the EC was higher in gymnasts than in controls (+27%). Conclusion. The better AP of the gymnasts (+79%) may be due to better arm strength conditioning and segmental coordination. EC and AP can be considered a suitable complementary parameter of jumping performance in gymnasts.


PubMed | INEFC Barcelona
Type: Journal Article | Journal: Biology of sport | Year: 2014

The objective of this study was to investigate the physiological indices of competitive routines in womens artistic gymnastics by characterizing post-exercise heart rate (HR), oxygen uptake (VO2) and peak blood lactate concentration (Lmax) in a group of eight young elite-oriented female gymnasts. HR was continuously monitored with Polar RS400 monitors during the test event simulating a competition environment. Within 5 s of the end of each routine, the breath-by-breath gas analyser mask was placed on the face to record VO2. VO2max was calculated by the backward extrapolation method of the VO2 recovery curve. Lmax was obtained during recovery (min 1, 3, 5, 7 and 10) subsequent to each event. One week later, HR, VO2 and Lmax were measured during an incremental continuous treadmill test. The treadmill test was confirmed as the assessment with the highest physiological demand. The gymnasts reached their highest values of HR (183-199 beats min(-1)), VO2/Bm (33-44 ml kg(-1) min(-1)) and Lmax (7-9 mmol l(-1)) in the floor and uneven bars exercises. The vault was the event with the lowest HR (154-166 beats min(-1)) and Lmax (2.4-2.6 mmol l(-1)), and the balance beam had the lowest VO2 (27-35 ml kg(-1) min(-1)). The mean relative peak intensities attained in the different events, which ranged from 65 to 85% of the individual VO2max and HRmax recorded in the laboratory, suggest that cardiorespiratory and metabolic demands are higher than previously indicated. The high percentage of VO2 measured, particularly after the floor event, suggests that aerobic power training should not be neglected in womens artistic gymnastics.

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