Changes in gait during constant pace treadmill running.

Treadmills are often used by runners when weather conditions are adverse or a specific training effect is desired. Athletes might respond to fatigue differently when running on a treadmill compared with overground conditions, where pace is typically more variable. The purpose of this study was to measure changes in gait parameters over the course of a 10-km treadmill run. Fifteen male competitive runners ran at a constant pace for 10 km at 103% of season's best time on an instrumented treadmill with in-dwelling force plates, and data were analyzed at 5 distances. Kinematic data were derived from high-speed videography and results compared between the early and late stages. Before halfway, step length increased and cadence decreased, whereas during the latter stages, there were significant decreases in impulse and maximum force. Contact time decreased and flight time increased continually, but otherwise most gait variables did not change. The changes in contact and flight times suggested that athletes altered their gait so that more time was spent airborne to allow the treadmill to pass under them. In general, however, the runners maintained their techniques throughout the run. Constant pace treadmill running might therefore be useful with the aim of running for a particular distance and speed with a consistent technique unaffected by factors such as gradient or fatigue. However, the increase in flight time might have aided the runners because of the nature of treadmill running, and athletes and coaches should note that this training effect is impractical during overground running

Red de elaboración de materiales en la asignatura de “Teoría y práctica del entrenamiento deportivo”

El objetivo del proyecto cuya memoria se presenta ha consistido en la preparación, diseño y elaboración, de los materiales de la asignatura del tercer curso de Grado “Teoría y práctica del entrenamiento deportivo”. Dichos materiales se utilizarán como documento base el próximo curso 2014/15. Hemos tomando como referencia un sistema basado en el crédito europeo y que supone un cambio radical, no solo a nivel estructural, sino también en relación con las metodologías docentes y la evaluación. En el ámbito del entrenamiento deportivo, el título de “Grado en ciencias de la actividad física y del deporte” distingue cinco asignaturas que abarcan un amplio abanico de contenidos. En su conjunto esta materia posee una gran carga en cuanto a número de créditos dentro del título, por lo que las competencias y contenidos deben definirse claramente. La asignatura “Teoría y práctica del entrenamiento deportivo” se imparte durante el primer cuatrimestre del tercer curso, por lo que es la base de todas las restantes asignaturas del ámbito del entrenamiento deportivo. El trabajo realizado ha tratado de conseguir, en un esfuerzo de coordinación docente, una metodología común adecuada para el desarrollo de los contenidos, la evaluación de los conocimientos y competencias adquiridos en esta asignatura

RELATIONSHIP BETWEEN RUNNING ECONOMY AND MECHANICAL CHARACTERISTICS OF TRICEPS SURAE ASSESSED WITH TENSIOMYOGRAPHY: A PILOT STUDY

Tensiomyography (TMG) is a non-invasive technique commonly used for evaluating muscle properties in highly trained athletes. The aim of our study was to evaluate the mechanical characteristics of m. triceps surae in competitive runners through TMG measurement and analyze if there was a relationship with running economy (RE). Nine male runners completed the study (mean±SD: age 40.4±9.0 years, body height 176.2±4.9 cm, body mass 70.7±9.4 kg, 10-km time 39.8±5.9 min, VO2peak 56.9 ± 6.5 mL kg-1 min-1). Each subject visited the lab on two occasions with 72h of rest between the trials. On the first day, an incremental test was performed to determine their ventilatory thresholds and peak oxygen consumption. On the second day, RE was evaluated on a treadmill at the velocity of their first ventilatory threshold (VT1), and mechanical characteristics of the soleus and gastrocnemius muscles were analyzed with TMG. Significant differences were found between the economic and non-economic runners in m. soleus in delayed time (Td), contraction time (Tc), and maximal radial displacement of the muscle belly (Dm). Also, significant differences were found in contraction time (Tc) in medium calf (MC) and in half relaxation time (Tr) in lateral twin (LT). The main finding of our study was that the runners with better RE showed greater stiffness in the triceps surae muscles, an aspect that seems to be associated with better performance in athlete runners.Key words: running economy (RE), tensiomyography (TMG), m. triceps surae, m. gastrocnemius, m. soleus</p

Muscle Activation in Middle-Distance Athletes with Compression Stockings

The aim of this study was to evaluate changes in electromyographic activity with the use of gradual compression stockings (GCSs) on middle-distance endurance athletes’ performance, based on surface electromyography measurement techniques. Sixteen well-trained athletes were recruited (mean ± SD: age 33.4 ± 6.3 years, VO2max 63.7 ± 6.3 mL·kg−1·min−1, maximal aerobic speed 19.7 ± 1.5 km·h). The athletes were divided into two groups and were assigned in a randomized order to their respective groups according to their experience with the use of GCSs. Initially, a maximum oxygen consumption (VO2max) test was performed to standardize the athletes’ running speeds for subsequent tests. Afterward, electromyographic activity, metabolic, and performance variables for each group were measured with surface electromyography. In addition, blood lactate concentration was measured, both with and without GCSs, during 10 min at 3% above VT2 (second ventilatory threshold), all of which were performed on the track. Next, surface electromyography activity was measured during a 1 km run at maximum speed. No significant changes were found in electromyography activity, metabolic and performance variables with GCSs use (p > 0.164) in any of the variables measured. Overall, there were no performance benefits when using compression garments against a control condition

Factors affecting training and physical performance in recreational endurance runners

Abstract: Endurance running has become an immensely popular sporting activity, with millions of recreational runners around the world. Despite the great popularity of endurance running as a recreational activity during leisure time, there is no consensus on the best practice for recreational runners to effectively train to reach their individual objectives and improve physical performance in a healthy manner. Moreover, there are lots of anecdotal data without scientific support, while most scientific evidence on endurance running was developed from studies observing both recreational and professional athletes of different levels. Further, the transference of all this information to only recreational runners is difficult due to differences in the genetic predisposition for endurance running, the time available for training, and physical, psychological, and physiological characteristics. Therefore, the aim of this review is to present a selection of scientific evidence regarding endurance running to provide training guidelines to be used by recreational runners and their coaches. The review will focus on some key aspects of the training process, such as periodization, training methods and monitoring, performance prediction, running technique, and prevention and management of injuries associated with endurance running

Changes in Triathletes’ Performance and Body Composition During a Specific Training Period for a Half-Ironman Race

The number of recreational athletes completing a Half-Ironman triathlon has increased exponentially in recent years. However, there is a lack of research on how to train for this kind of an event. The purpose of this study was thus to analyse triathletes’ changes in performance and body composition following a triathlon-specific training period. Fourteen male amateur triathletes completed a 7-week period of general training and a 13-week period of specific training for a Half-Ironman triathlon. Anthropometric measures and performance tests were carried out to assess the effects of the specific training program. Results showed that the pre-test value of VO2max for cycling was inversely correlated not only with the percentage of change in cycling performance, but also with the percentage change in several variables of running performance. In swimming, inverse correlations were observed between the time of the first 800 m test and the time percentage change for this test, but not with the percentage change in the performance of other segments of the race. Moreover, the somatotype component of endomorphy and the fat mass percentage of the first anthropometry were highly correlated with the percentage change in VO2max in the run segment. These results highlight the importance of providing individualised training, considering that the same training program had a different impact on recreational triathletes belonging to the same group. Amateur athletes with higher initial performance levels probably need a greater amount of training to achieve improved adaptation

Intake of animal protein blend plus carbohydrate improves body composition with no impact on performance in endurance athletes

The impact of animal blend protein supplements in endurance athletes is scarcely researched. We investigated the effect of ingesting an admixture providing orange juice and protein from beef and whey versus carbohydrate alone on body composition and performance over a 10-week training period in male endurance athletes. Participants were randomly assigned to a protein (CHO+PRO, n=15) or a non-protein isoenergetic carbohydrate (CHO, n=15) group. Twenty grams of supplement mixed with orange juice was ingested post-workout or before breakfast on non-training days. Measurements were performed pre- and post-intervention on body composition (by dual-energy X-ray absorptiometry), peak oxygen consumption (VO2peak), and maximal aerobic speed (MAS). Twenty-five participants (CHO+PRO, n=12; CHO, n=13) completed the study. Only the CHO+PRO group significantly (p<0.05) reduced whole body fat (mean}SD) (-1.02 } 0.6 kg), total trunk fat (-0.81 } 0.9 kg) and increased total lower body lean mass (+0.52 } 0.7 kg), showing close to statistically significant increases of whole-body lean mass (+0.57 } 0.8 kg, p=0.055). Both groups reduced (p<0.05) visceral fat (CHO+PRO, -0.03 } 0.1 kg; CHO, -0.03 } 0.5 kg) and improved the speed at MAS (CHO+PRO, +0.56 } 0.5 km.h-1; CHO, +0.35 }0.5 km.h-1). Although consuming animal blend protein mixed with orange juice over 10 weeks helped to reduce fat mass and to increase lean mass, no additional performance benefits in endurance runners were observed

Is there an association between ACTN3 R577X polymorphism and muscle power phenotypes in young, non-athletic adults?

We investigated the association between ACTN3 R577X polymorphism and jumping (vertical squat and counter-movement jump tests) and sprint ability (30 m dash) in non-athletic, healthy young adults [N=284 (217 male), mean (SD) age: 21 (2) years]. We analyzed the differences in the study phenotypes among ACTN3 R577X genotypes by one-way analysis of covariance before and after adjusting for sex, age, weight and height (confounders). We also compared the genotype and allele frequencies between those with the best and worst results in the aforementioned tests (≥90th vs 0.05). In summary, α-actinin-3 deficiency does not negatively influence the ability to generate explosive leg muscle power in a young non-athletic population