Luca Paolo Ardigò

A paradigm of uphill running.

The biomechanical management of bioenergetics of runners when running uphill was investigated. Several metabolic and mechanical variables have been studied simultaneously to spread light on the locomotory strategy operated by humans for effective locomotion. The studied variables were: heart rate, heart rate variability, oxygen intake and blood lactate, metabolic cost, kinematics, ground reaction force and muscular activity. 18 high-level competitive male runners ran at 70% VO2max on different uphill slope conditions: 0%, 2% and 7%. Modifications were significant in almost all variables studied, and were more pronounced with increasing incline. Step frequency/length and ground reaction force are adjusted to cope with both the task of uphill progression and the available (limited) metabolic power. From 0% to 7% slope, step frequency and ground reaction force and metabolic cost increased concurrently by 4%, 12% and 53%, respectively (with a 4% step length decrease as well). It is hypothesised that this biomechanical management is allowed by an environment-body communication performed by means of specific muscular activity.

Measured and predicted mechanical internal work in human locomotion.

Predictive methods estimating mechanical internal work (W(int), i.e., work to accelerate limbs with respect to BCOM during locomotion) are needed in absence of experimental measurements. A previously proposed model equation predicts such a parameter based upon velocity, stride frequency, duty factor, and a compound critical term (q) accounting for limb geometry and inertial properties. That first predicted W(int) estimate (PW(int)) has been validated only for young males and for a limited number of horses. The present study aimed to extend the comparison between model predictions and experimentally measured W(int) (MW(int)) data on humans with varying gender, age, gait, velocity, and gradient. Seventy healthy subjects (males and females; 7 age groups: 6-65 years) carried out level walking and running on treadmill, at different velocities. Moreover, one of the subject groups (25-35 years) walked and ran also at several uphill/downhill gradients. Reference values of q represent the main important results: (a) males and females have similar q values; (b) q is independent on velocity and gradient. Also, different data filtering depth was found to affect MW(int) and, indirectly, PW(int), thus also the reference q values here obtained (0.08 in level, 0.10 in gradient) suffer a--20% underestimation with respect to the previous predicting model. Despite of this effect, the close match between MW(int) and PW(int) trends indicates that the model equation could be satisfactorily applied, in various locomotion conditions.

Metabolic optimisation of the basketball free throw

Abstract The free throw (FT) is a fundamental basketball skill used frequently during a match. Most of actual play occurs at about 85% of maximum heart rate (HR). Metabolic intensity, through fatigue, may influence a technically skilled move as the FT is. Twenty-eight under 17 basketball players were studied while shooting FTs on a regular indoor basketball court. We investigated FT accuracy in young male basketball players shooting at three different HRs: at rest, at 50% and at 80% of maximum experimentally obtained HR value. We found no significant FT percentage difference between rest and 50% of the maximum HR (FT percentage about 80%; P > 0.05). Differently, at 80% of the maximum HR the FT percentage decreased significantly by more than 20% (P < 0.001) down to about 60%. No preliminary warm-up is needed before entering game for the FT accuracy. Furthermore, we speculate that time-consuming, cooling-off routines usually performed by shooters before each FT may be functional to improve its accuracy.

Signal or noise, a statistical perspective

Best practices about the appropriate use of statistical tools in sport and clinical sciences are increasingly being fostered. For the sake of science, the interpretation of the result of an experiment is the central key, which features the interpretation of the phenomenon. Recently, an interesting article in PNAS (1) shows that musical agency reduces perceived exertion during strenuous physical performance. Considering the experimental approach and data analysis, we also perceived this phenomenon as intriguing. However, the methodology approach requires stronger certainty because science must first reduce uncertainties to interpret effectively the collected results. We will discuss some points in this letter to clarify the question of “signal” and “noise.” In the study in question, the age range was wide (18–59 y): a different maturation level significantly affects the perceived exertion (2). The two to three different conditions were counterbalanced, but administering all of them during the same day, albeit at different times (3), could have caused an uncontrolled fatigue effect. Not all measures (1) have been verified in terms of measurement reliability (4). This point is crucial, because the authors only report laboratory spirometer VO2 accuracy. Given the physiological–psychological translational nature of this study, the experimental design is rather complex, making replication difficult. We agree that the “ratio” approach is fascinating, but, because the original results are not provided, the study repeatability is impaired. Considering the psycho-physical nature of the Borg scale, its poor accuracy (5), and the related documented relationship with age (2), the high variability featured in the study results of Fritz et al. seems to reflect more interindividual variability (noise) than the effect of a potential neuro-physiological phenomenon (signal).

Anatomically Asymmetrical Runners Move More Asymmetrically at the Same Metabolic Cost

We hypothesized that, as occurring in cars, body structural asymmetries could generate asymmetry in the kinematics/dynamics of locomotion, ending up in a higher metabolic cost of transport, i.e. more ‘fuel’ needed to travel a given distance. Previous studies found the asymmetries in horses’ body negatively correlated with galloping performance. In this investigation, we analyzed anatomical differences between the left and right lower limbs as a whole by performing 3D cross-correlation of Magnetic Resonance Images of 19 male runners, clustered as Untrained Runners, Occasional Runners and Skilled Runners. Running kinematics of their body centre of mass were obtained from the body segments coordinates measured by a 3D motion capture system at incremental running velocities on a treadmill. A recent mathematical procedure quantified the asymmetry of the body centre of mass trajectory between the left and right steps. During the same sessions, runners’ metabolic consumption was measured and the cost of transport was calculated. No correlations were found between anatomical/kinematic variables and the metabolic cost of transport, regardless of the training experience. However, anatomical symmetry significant correlated to the kinematic symmetry, and the most trained subjects showed the highest level of kinematic symmetry during running. Results suggest that despite the significant effects of anatomical asymmetry on kinematics, either those changes are too small to affect economy or some plastic compensation in the locomotor system mitigates the hypothesized change in energy expenditure of running.

The Impact of Jumping during Recovery on Repeated Sprint Ability in Young Soccer Players

This study compared the effect of counter-movement-jump (CMJ)-based recovery on repeated-sprint-ability (RSA). Eighteen male footballers (16 ± 0 years, 65 ± 10 kg, 1.74 ± 0.10 m) performed three RSA-tests. RSA-1/-3 were performed according to standard procedures, while three CMJs (over 10″) – as a potential fatigue-determinant and/or running mechanics interference – were administered during RSA-2 recoveries. RSA performance, exercise effort (fatigue index [FI], rating of perceived exertion [RPE], blood lactate concentration [BLa]), simple kinematics (steps number), vertical-jump characteristics (stretch-shortening-cycle-efficiency [SSCE] assessed before/after RSA) were investigated. ANOVA showed no differences between RSA-1,-3. During RSA-2, performance was lower than RSA-1/-3, while steps number did not change. During RSA-2, FI, BLa, RPE were higher than RSA-1/-3 (FI +21.10/+20.43%, P<0.05; BLa +16.25/+13.34%, P<0.05; RPE +12.50/+9.57%, P<0.05). During RSA-2, SSCE, as the CMJ/squat-jump-height-ratio, was not significantly different from RSA-1/-3. Passive recovery RSA allows better performance. Yet, RSA CMJ-based recovery is effective in increasing training load (FI, BLa, RPE) without perturbing running mechanics (simple kinematics, SSCE).

Repeated sprint ability related to recovery time in young soccer players

This study aimed to describe the influence of recovery duration during a repeated sprint ability (RSA) test (6 × 40 m) by investigating a number of variables, such as general performance, metabolic demand, and muscular stretch-shortening performance. Seventeen male soccer outfield players (16 ± 0 years, 66 ± 10 kg) performed three field shuttle-running tests with 15, 20, and 25-sec recoveries. In addition to specific shuttle test’s variables, blood lactate concentration and vertical jump height were assessed. Resulting measures were highly reliable (intra-class correlation coefficient up to 0.86). 25-sec recovery improved test performance (−3% total time from 15-sec to 25-sec recovery), vertical jump height (+7% post-test height from 15-sec to 25-sec recovery), and decreased blood lactate accumulation (−33% post-test from 15-sec to 25-sec recovery). Study findings suggest that metabolic acidosis plays a role in worsening performance and fatigue development during the shuttle test. A 25-sec recovery duration maximized performance, containing metabolic-anaerobic power involvement and muscular stretch-shortening performance deterioration during a RSA test.

Effect of Small-Sided Games and Repeated Shuffle Sprint Training on Physical Performance in Elite Handball Players

Abstract Dello Iacono, A, Ardigò, LP, Meckel, Y, and Padulo, J. Effect of small-sided games and repeated shuffle sprint training on physical performance in elite handball players. J Strength Cond Res 30(3): 830–840, 2016—This study was designed to compare the effects of small-sided games (SSGs) and repeated shuffle sprint (RSS) training on repeated sprint ability (RSA) and countermovement jump (CMJ) tests performances of elite handball players. Eighteen highly trained players (24.8 ± 4.4 years) were assigned to either SSG or RSS group training protocols twice a week for 8 weeks. The SSG training consisted of 5 small-sided handball games with 3-a-side teams excluding goalkeepers. The RSS consisted of 2 sets of 14–17 of 20-m shuttle sprints and 9-m jump shots interspersed by 20-second recoveries. Before and after training, the following performance variables were assessed: speed on 10-m and 20-m sprint time, agility and RSA time, CMJ height, standing throw, and jump shot speed. Significant pre-to-post treatment improvements were found in all the assessed variables following both training protocols (multivariate analysis of variance, p ⩽ 0.05). There was a significantly greater improvement on 10-m sprint, CMJ, and jump shooting, after the RSS in comparison with SSG training (+4.4% vs. +2.4%, +8.6% vs. +5.6%, and +5.5% vs. +2.7%, respectively). Conversely, agility and standing throwing showed lower improvements after RSS in comparison with SSG (+1.0% vs. +7.8% and +1.6% vs. +9.0%, respectively). These results indicate that these training methods are effective for fitness development among elite adult handball players during the last period of the competitive season. Specifically, SSG seems to be more effective in improving agility and standing throw, whereas RSS seems preferable in improving 10-m sprint, CMJ, and jump shot.

Evaluating BCI devices: a statistical perspective

To the Editor, Several letters on statistical procedures and scientific approaches entitled ‘Statistics: all together not’ (Hopkins et al. 2011a, 2011b, 2011c, 2011d) and ‘Concentric and eccentric: muscle contraction or exercise?’ (Padulo, Dal Pupo, et al. 2013; Padulo, Laffaye, Chamari, Concu 2013; Padulo, Laffaye, Ardigò, Chamari 2013) have been published in scientific journals between 2011 and 2013. These aim to encourage improved reporting of methodological procedures and correct usage of statistics in scientific articles. In 2012, a paper was published in Ergonomics, examining the potential use of consumer brain computer interface (BCI) devices for research and experimentation (Ekandem et al. 2012). Ekandem et al. describe BCI devices as ‘ . . . physical devices that allow one-way communication from the human brain to an external machine by interpreting electroencephalography brain wave data’. This is clearly an interesting and important area of research. We wish to argue, however, that evaluating the feasibility of using consumer BCIs within scientific research (or even as lie detector equipment) requires a more rigorous scientific approach and reporting of details. We do not believe that the paper provides sufficient information to support its reasoning and conclusions. The aim of this letter is to identify, in our opinion, important omissions and errors. The following points are intended to establish the scientific standard we consider to be essential with studies of the nature described by Ekandem et al. (2012):

Formetric 4D Rasterstereography

This paper is a comment on “Intra- and interday reliability of spine rasterstereography” [1]. We think that supporting the feasibility of using the rasterstereographic tool Formetric 4D, both as a diagnostic tool and in scientific research, requires much more scientific exactness. The purpose of this paper is to underline what we consider to be substantial omission or error.