Changes of direction during high-intensity intermittent runs: neuromuscular and metabolic responses

Abstract

BackgroundThe ability to sustain brief high-intensity intermittent efforts (HIE) is meant to be a major attribute for performance in team sports. Adding changes of direction to HIE is believed to increase the specificity of training drills with respect to game demands. The aim of this study was to investigate the influence of 90°-changes of direction (COD) during HIE on metabolic and neuromuscular responses.MethodsEleven male, team sport players (30.5 ± 3.6 y) performed randomly HIE without (straight-line, 2×[10× 22 m]) or with (2×[10× ~16.5 m]) two 90°-COD. To account for the time lost while changing direction, the distance for COD runs during HIE was individually adjusted using the ratio between straight-line and COD sprints. Players also performed 2 countermovement (CMJ) and 2 drop (DJ) jumps, during and post HIE. Pulmonary oxygen uptake (VO2), quadriceps and hamstring oxygenation, blood lactate concentration (Δ[La]b), electromyography amplitude (RMS) of eight lower limb muscles and rating of perceived exertion (RPE) were measured for each condition.ResultsDuring HIE, CODs had no substantial effects on changes in VO2, oxygenation, CMJ and DJ performance and RPE (all differences in the changes rated as unclear). Conversely, compared with straight-line runs, COD-runs were associated with a possibly higher Δ[La]b (+9.7 ± 10.4%, with chances for greater/similar/lower values of 57/42/0%) and either a lower (i.e., −11.9 ± 14.6%, 2/13/85 for semitendinosus and −8.5 ± 9.3%, 1/21/78 for lateral gastrocnemius) or equivalent decrease in electromyography amplitude.ConclusionAdding two 90°-CODs on adjusted distance during two sets of HIE is likely to elicit equivalent decreases in CMJ and DJ height, and similar cardiorespiratory and perceptual responses, despite a lower average running speed. A fatigue-induced modification in lower limb control observed with CODs may have elicited a selective reduction of electromyography activity in hamstring muscles and may induce, in turn, a potential mechanical loss of knee stability. Therefore, changing direction during HIE, with adjusted COD running distances, might be an effective training practice 1) to manipulate some components of the acute physiological load of HIE, 2) to promote long-term COD-specific neuromuscular adaptations aimed at improving performance and knee joint stability.

Effects of Small-Sided Game Variation on Changes in Hamstring Strength

“…Whilst we appreciate that eccentric hamstring strength would be a more suitable indication of this, the loss in isometric force production is likely to be related (24). Furthermore, hamstring fatigue is associated with a loss of motor activity in the local musculature and can also affect mechanical knee stability (26,16) during soccer-type activities, such as jump landing (39) or COD (14). Based on these observations, reduced hamstring force is likely to predispose the player to heightened risk of injury during high-velocity movements (such as those observed in the large SSGs) or during other soccer-type activities.…”

“…Hamstring function is integral to the performance of soccer-specific movement skills, such as decelerating, jump landing and changes of direction (COD), where the hamstrings provide stability to the knee joint (12,14,32,29). During kicking actions, the hamstrings contract concentrically at the start of the backswing on the striking leg, and eccentrically activate to decelerate the lower limb to control the follow-through (31,8).…”

The specificity of the Loughborough Intermittent Shuttle Test for recreational soccer players is independent of their intermittent running ability

“…LIST is performed on a 20 -m shuttle run course, in order to mimic the several changes of direction (COD) in which SP are involved during a match. Although the inclusion of COD into the intermittent exercise did not modify the metabolic response and the RPE, the lower limb muscle activity was affected by COD compared to straight-only inter-260 mittent exercise (Hader, Mendez-Villanueva, Ahmaidi, Williams, & Buchheit, 2014). Quadriceps, hamstrings and gastrocnemii activity resulted greater when COD is included into the intermittent exercise, mainly due to the increasing knee stabilization (Besier, Lloyd, & Ackland, 2003).…”

“…Even if the IR1 does include the COD in its protocol, the duration of the LIST (and soccer match) is greatly longer than IR1. Furthermore, the inclusion of COD in training can help to manage fatigue from both a psychological and metabolic points of 270 view (Hader et al, 2014). Therefore, considering the overall sports' backgrounds of the two selected populations, it is likely that SP can be more conditioned to COD than non-SP.…”

Análisis de las estrategias de entrenamiento para la mejora del rendimiento en la capacidad de repeitir sprints en los deportes colectivos

“…Mientras que el entrenamiento mediante sprint repetidos es efectivo para una amplia variedad de componentes del rendimiento físico (Taylor, Macpherson, Spears, & Weston, 2015), hay consideraciones clave en la programación del entrenamiento, especialmente relacionadas con el volumen (número de sprints y distancia de sprint) la densidad (relación trabajo/recuperación) y el tipo de esfuerzo (línea recta o cambio de dirección), para inducir adaptaciones positivas en el rendimiento. La competición no solo demanda esfuerzos en línea recta en los deportes colectivos, sino la realización de cambios de dirección (Stolen, Chamari, Castagna, & Wisloff, 2005), por lo que el entrenamiento de sprint repetidos con cambios de dirección podría originar adaptaciones que mejoren el rendimiento en el RSA y en la competición (Hader, Mendez-Villanueva, Ahmaidi, Williams, & Buchheit, 2014). Estos cambios dirección pueden estimular en mayor medida el componente neuromuscular, mejorando la fuerza explosiva de los deportistas (Attene et al, 2015), pero a costa de una menor velocidad alcanzada durante el entrenamiento.…”