Artículos científicos

Improving the value of fitness testing for football

Por Iñigo Mujika , el 21 de mayo de 2014

Material para tests de rendimiento (Foto: Iñigo Mujika)

David B. Pyne, Matt Spencer, Iñigo Mujika.

International Journal of Sports Physiology and Performance. Volume 9, Issue 3, May 2014, 511 – 514.

Abstract

One of the challenges for sports scientists working in football is to balance the needs for routine fitness testing with daily fatigue and well-being monitoring to best manage the physical preparation of players. In this commentary, the authors examine contemporary issues of fitness testing in football to identify ways of improving the value of routine testing and monitoring. A testing program must be well planned and organized to ensure that the results are useful. Different tests can be employed for younger and older players. A rigorous approach to analysis and interpretation of results is desirable, and database management must address both short- and long-term requirements of players, staff, and programs.

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Identifying optimal overload and taper in elite swimmers over time

Por Iñigo Mujika , el 4 de diciembre de 2013

Philippe Hellard, Marta Avalos, Christophe Hausswirth, David Pyne, Jean-Francois Toussaint, Iñigo Mujika.

Journal of Sports Science and Medicine (2013) 12, 668 – 678

The aim of this exploratory study was to identify the most influential training designs during the final six weeks of training (F6T) before a major swimming event, taking into account athletes’ evolution over several seasons. Fifteen female and 17 male elite swimmers were followed for one to nine F6T periods. The F6T was divided into two sub-periods of a three-week overload period (OP) and a three-week taper period (TP). The final time trial performance was recorded for each swimmer in his or her specialty at the end of both OP and TP. The change in performances (ΔP) between OP and TP was recorded. Training variables were derived from the weekly training volume at several intensity levels as a percentage of the individual maximal volume measured at each intensity level, and the individual total training load (TTL) was considered to be the mean of the loads at these seven intensity levels. Also, training patterns were identified from TTL in the three weeks of both OP and TP by cluster analysis. Mixed-model was used to analyse the longitudinal data. The training pattern during OP that was associated with the greatest improvement in performance was a training load peak followed by a linear slow decay (84 ± 17, 81 ± 22, and 80 ± 19 % of the maximal training load measured throughout the F6T period for each subject, Mean ± SD) (p < 0.05). During TP, a training load peak in the 1st week associated with a slow decay design (57 ± 26, 45 ± 24 and 38 ± 14%) led to higher ΔP (p < 0.05). From the 1st to 3rd season, the best results were characterized by maintenance of a medium training load from OP to TP. Progressively from the 4th season, high training loads during OP followed by a sharp decrease during TP were associated with higher ΔP.

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Do olympic athletes train as in the Paleolithic Era?

Por Iñigo Mujika , el 31 de agosto de 2013

Elefantes sudafricanos (Foto: Iñigo Mujika)

Boullosa DA, Abreu L, Varela-Sanz A, Mujika I.

Sports Medicine. 2013 Aug 20.

Cada 4 años, aproximadamente 10.000 deportistas participan en los Juegos Olímpicos. Estos deportistas han dedicado varios años de entrenamiento físico para lograr el mejor rendimiento posible en un día determinado. Su preparación ha sido apoyada por entrenadores expertos y un ejército de científicos del deporte, cuya responsabilidad general es asegurarse de que los deportistas están en una forma óptima para su prueba. Aunque cada deportista se prepara específicamente para los retos fisiológicos únicos de su prueba, todos ellos tienen una característica en común: son Homo sapiens. Comparten un genoma único que es el resultado de fuerzas evolutivas que se escapan a su control individual. Aunque se ha demostrado que los estudios sobre la influencia de distintos polimorfismos genéticos sobre determinadas pruebas deportivas tienen una utilidad limitada, existen evidencias –desde la biología molecular hasta medidas de cuerpo entero– que sugieren que las adaptaciones al entrenamiento aumentan cuando el estímulo se asemeja al patrón de actividad de los ancestros humanos. Dado que los cambios genéticos evolutivos ocurren despacio en el Homo sapiens, y que los patrones tradicionales de actividad física y dieta del Homo sapiens han sufrido grandes cambios rápidamente en siglos recientes, proponemos que los humanos modernos están mejor adaptados fisiológicamente a modos de entrenamiento y estrategias nutricionales similares a aquellos con las que evolucionaron sus ancestros homínidos, y no aquellos propuestos por las sociedades modernas. Semejante patrón ancestral se caracterizaba básicamente por la prevalencia de esfuerzos diarios de actividades aeróbicas prolongadas, de baja intensidad, con impulsos periódicos intercalados de actividad de corta duración y alta intensidad. En algunas ocasiones, estos patrones de actividad se llevaban a cabo con baja disponibilidad de carbohidratos. Las actividades específicas que mejoraban la fuerza y la potencia se realizaban normalmente después de las actividades aeróbicas. Presentamos evidencias científicas para apoyar la idoneidad de este modelo, y proponemos que los estudios en el futuro deberían abordar esta hipótesis en multitud de actividades deportivas diferentes, evaluando las respuestas genéticas y los efectos sobre el rendimiento de diferentes estímulos de entrenamiento. Esta información aportaría datos sobre los que científicos del deporte y entrenadores podrían preparar mejor a los deportistas y gestionar su proceso de entrenamiento.

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Optimizing strength training for running and cycling endurance performance: A review

Por Iñigo Mujika , el 13 de agosto de 2013

Rønnestad BR, Mujika I.

Scandinavian Journal of Medicine & Science in Sports. 2013 Aug 5. doi: 10.1111/sms.12104.

Here we report on the effect of combining endurance training with heavy or explosive strength training on endurance performance in endurance-trained runners and cyclists. Running economy is improved by performing combined endurance training with either heavy or explosive strength training. However, heavy strength training is recommended for improving cycling economy. Equivocal findings exist regarding the effects on power output or velocity at the lactate threshold. Concurrent endurance and heavy strength training can increase running speed and power output at VO2max (Vmax and Wmax , respectively) or time to exhaustion at Vmax and Wmax. Combining endurance training with either explosive or heavy strength training can improve running performance, while there is most compelling evidence of an additive effect on cycling performance when heavy strength training is used. It is suggested that the improved endurance performance may relate to delayed activation of less efficient type II fibers, improved neuromuscular efficiency, conversion of fast-twitch type IIX fibers into more fatigue-resistant type IIA fibers, or improved musculo-tendinous stiffness.

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Effect of training cessation on muscular performance: A meta-analysis

Por Iñigo Mujika , el 2 de febrero de 2013

Bosquet L, Berryman N, Dupuy O, Mekary S, Arvisais D, Bherer L, Mujika I.

Scandinavian Journal of Medicine & Science in Sports. doi: 10.1111/sms.12047

The purpose of this study was to assess the effect of resistance training cessation on strength performance through a meta-analysis. Seven databases were searched from which 103 of 284 potential studies met inclusion criteria. Training status, sex, age, and the duration of training cessation were used as moderators. Standardized mean difference (SMD) in muscular performance was calculated and weighted by the inverse of variance to calculate an overall effect and its 95% confidence interval (CI). Results indicated a detrimental effect of resistance training cessation on all components of muscular performance: [submaximal strength; SMD (95% CI) = -0.62 (-0.80 to -0.45), P <  0.01], [maximal force; SMD (95% CI) = -0.46 (-0.54 to -0.37), P < 0.01], [maximal power; SMD (95% CI) = -0.20 (-0.28 to -0.13), P < 0.01]. A dose-response relationship between the amplitude of SMD and the duration of training cessation was identified. The effect of resistance training cessation was found to be larger in older people (> 65 years old). The effect was also larger in inactive people for maximal force and maximal power when compared with recreational athletes. Resistance training cessation decreases all components of muscular strength. The magnitude of the effect differs according to training status, age or the duration of training cessation.

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Warm-Up Intensity and Duration’s Effect on Traditional Rowing Time-Trial Performance

Por Iñigo Mujika , el 23 de mayo de 2012

Iñigo Mujika, Rafa González de Txabarri, Sara Maldonado-Martín, and David B. Pyne

International Journal of Sports Physiology and Performance, 2012, 7, 186-188

The warm-up procedure in traditional rowing usually involves continuous low-intensity rowing and short bouts of intense exercise, lasting about 60 min. Purpose: To compare the effects of a traditional and an experimental 30-min warm-up of lower intensity on indoor rowing time-trial performance. Methods: Fourteen highly trained male rowers (age 25.9 ± 5.3 y, height 1.86 ± 0.06 m, mass 80.4 ± 5.2 kg, peak aerobic power 352.0 ± 24.4 W; mean ± SD) performed 2 indoor rowing trials 12 d apart. Rowers were randomly assigned to either LONG or SHORT warm-ups using a crossover design, each followed by a 10-min all-out fixed-seat rowing-ergometer time trial. Results: Mean power output during the time trial was substantially higher after SHORT (322 ± 18 vs 316 ± 17 W), with rowers generating substantially more power in the initial 7.5 min of the time trial after SHORT. LONG elicited substantially higher mean warm-up heart rate than SHORT (134 ± 11 vs 121 ± 13 beats/min), higher pre–time-trial rating of perceived exertion (10.2 ± 1.4 vs 7.6 ± 1.7) and blood lactate (1.7 ± 0.4 mM vs 1.2 ± 0.2 mM), but similar heart rate (100 ± 14 vs 102 ± 9 beats/min). No substantial differences were observed between LONG and SHORT in stroke rate (39.4 ± 2.0 vs 39.4 ± 2.2 strokes/min) or mean heart rate (171 ± 6 vs 171 ± 8 beats/min) during the time trial, nor in blood lactate after it (11.8 ± 2.5 vs 12.1 ± 2.0 mM). Conclusion: A warm-up characterized by lower intensity and shorter duration should elicit less physiological strain and promote substantially higher power production in the initial stages of a rowing time trial.

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Fitness determinants of repeated-sprint ability in highly trained youth football players

Por Iñigo Mujika , el 9 de abril de 2012

Matt Spencer, David Pyne, Juanma Santisteban, Iñigo Mujika.

International Journal of Sports Physiology and Performance. 2011 Dec; 6(4):497-508.

Variations in rates of growth and development in young football players can influence relationships among various fitness qualities. Purpose: To investigate the relationships between repeated-sprint ability and other fundamental fitness qualities of acceleration, agility, explosive leg power, and aerobic conditioning through the age groups of U11 to U18 in highly trained junior football players. Methods: Male players (n = 119) across the age groups completed a fitness assessment battery over two testing sessions. The first session consisted of countermovement jumps without and with arm swing, 15-m sprint run, 15-m agility run, and the 20-m Shuttle Run (U11 to U15) or the Yo-Yo Intermittent Recovery Test, Level 1 (U16 to U18). The players were tested for repeated-sprint ability in the second testing session using a protocol of 6 × 30-m sprints on 30 s with an active recovery. Results: The correlations of repeated-sprint ability with the assorted fitness tests varied considerably between the age groups, especially for agility (r = .02 to .92) and explosive leg power (r = .04 to .84). Correlations of repeated sprint ability with acceleration (r = .48 to .93) and aerobic conditioning (r = .28 to .68) were less variable with age. Conclusion: Repeated-sprint ability associates differently with other fundamental fitness tests throughout the teenage years in highly trained football players, although stabilization of these relationships occurs by the age of 18 y. Coaches in junior football should prescribe physical training accounting for variations in short-term disruptions or impairment of physical performance during this developmental period.

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