Marcello Faina

The VO2 slow component in swimming

Abstract All studies on the oxygen uptake (V˙O2) slow component have been carried out for the sporting disciplines of cycling or running, but never for swimming. Considering that front crawl swimming is a sport discipline that is fundamentally different from both running and cycling, the aim of this study was to verify whether this slow component also appears in swimming. Six elite pentathletes were tested in a swimming flume while front crawl swimming to exhaustion. Swimming velocity for the slow component test was determined as v50Δ=CV+[(vV˙O2peak−CV)/2], where CV is the critical velocity and vV˙O2peak the lowest velocity at which peak V˙O2 occurred. To set the subjects CV, expressed as the slope of a straight line that describes the correlation between swimming distance and time, the record times over three swimming distances were recorded in a 50 m swimming pool. The vV˙O2peak was measured by means of an incremental test in the swimming flume. Gas exchange was measured by means of a telemetric metabolimeter (K4 RQ, Cosmed, Italy) that was connected to a snorkel. The slow component was found in all subjects, with a mean (SD) value of 239 (194) mlO2 · min−1. Therefore, although front crawl swimming is fundamentally different from both running and cycling, it appears that it also incurs a V˙O2 slow component. The origin of this phenomenon, however, is even more uncertain than for the other sport disciplines.

Amateur boxing in the last 59 years. Impact of rules changes on the type of verdicts recorded and implications on boxers’ health

Background/aim Several changes have occurred in Olympic boxing (OB) in the last few decades, influencing the results in official competitions. The aim of this study was to assess how the evolution of rules changed the rate of the results that can influence boxers’ health. Methods From a web-research, the results of OB tournaments from 1952 to 2011 were reviewed (29 357 bouts). For each event, rate of knockout (KO), referee-stop contest (RSC), RSC-Head (RSCH), RSC-Injury (RSCI), RSC-Outclassed (RSCO), abandon, disqualification and points decisions were recorded. In our analysis we investigated the changes that occurred after the introduction of the standing-count rule (1964), mandatory head guard (1984), computerised scoring system (1992), RSCO (2000–2009) and modification of bout formula 3×3 min rounds (3×3, until 1997, 5×2 min rounds (5×2) until 1999, 4×2 min rounds (4×2) until 2008, 3×3 from 2009). Results The most important results were: (1) an RSCI rate increase (0.72–2.42%, p<0.03) after the standing-count rule; (2) a lower RSCI (0.60%, p<0.001) and higher RSCH (1.31–4.92%, p<0.001) and RSC (9.71–13.05%, p<0.03) rate with mandatory head guard; (3) a KO rate reduction (6.44–2.09%, p<0.001) with the computerised scoring system; (4) an RSC (13.15–5.91%, p<0.05) and RSCH (4.23–1.41%, p<0.001) rate reduction comparing 5×2–4×2 bouts. Conclusions In the last six decades, along with rule changes in OB, a clear reduction of health challenging results was observed. In the near future, older rules will be adopted (no head guard and a manual scoring system). Continued medical surveillance is important to ensure that new rule changes do not result in poor medical outcomes for the boxers.

Evaluation of intensity during an interval Spinning® session: a field study

The purpose of the present study was to evaluate metabolic and mechanical parameters of Spinning® and to verify if the intensities remain within the American College of Sports Medicine recommendations. Fifteen participants (8 males: 39.0±2.0 years; 70.0±2.0 kg; 177.0±2.0 cm, 58.0±3.0 ml/kg/min; and 7 females: 33.6±5.5 years; 56.6±4.4 kg; 165.0±4.6 cm; 48.8±5.5 ml/kg/min) performing an interval Spinning® session had their heart rate (HR), oxygen consumption (VO2) and power output (W) measured. At the beginning and during the Spinning® session, a blood sample was taken for lactate measurements. Statistical difference between phases was performed with ANOVA repeated measure design and a Chi-square test to calculate the frequency of distribution of HRs. The energy cost of the activity was 3367±159 kJ/h (804±38 kcal/h). Participants worked on average at 54% Wmax, 79% VO2max and 86% HRmax. Participants spent 80% of the session above the HR suggested by the instructor. Peak lactate measured was 5.3±0.69 mmol/l. The registered intensity was higher than the guidelines for healthy activities. Therefore Spinning® should be considered a “very intense” activity and particular attention should be paid to novel or unfit participants because no feedback is provided during the session to control the intensity participants are working at.

Criterion and longitudinal validity of a fixed-distance incremental running test for the determination of lactate thresholds in field settings

La Torre, A, Fiorella, P, Santos, TM, Marcello, F, Mauri, C, and Impellizzeri, FM. Criterion and longitudinal validity of a fixed-distance incremental running test for the determination of lactate thresholds in field setting. J Strength Cond Res 26(1): 146–151, 2012—The aim of this study was to examine the criterion validity of 2 lactate thresholds (LTs, intensity corresponding to 1 mmol·L−1 above baseline; onset of blood lactate accumulation, intensity at 4 mmol·L−1) determined with a fixed-distance incremental field test by assessing their correlation with those obtained using a traditional fixed-time laboratory protocol. A second aim was to verify the longitudinal validity by examining the relationships between the changes in LTs obtained with the 2 protocols. To determine the LTs, 12 well-trained male middle and long distance amateur and competitive runners training from 4 to 7 d·wk−1 (age 25 [5] years, body mass 66 [5] kg, estimated &OV0312;O2max 58.6 [4.9] ml·min−1·kg−1, SD in parentheses) performed in 2 separate sessions an incremental running test on the field starting at 12 km·h−1 and increasing the speed by 1 km·h−1 every 1,200 m (FixD test) and an incremental treadmill test in the laboratory starting at 12 km·h−1 and increasing the speed by 1 km·h−1 every 6 minutes. The 2 tests were repeated after 6–12 weeks. A nearly perfect relationship was found between the running speeds at LTs determined with the 2 protocols (r = 0.95 [CI95% 0.83–0.99]; p < 0.001). The correlations between longitudinal changes in LTs were very large (0.78 [0.32–0.95; p = 0.006]). The heart rate corresponding to the LTs were not significantly different. This study showed the criterion and longitudinal validity of LTs determined with a protocol consisting of fixed-distance intervals performed in field setting.

VO2 Kinetics during Moderate Effort in Muscles of Different Masses and Training Level

Purpose. To examine the relative importance of central or peripheral factors in the on-transient VO2 response dynamics to exercise with “trained” and relatively “untrained” muscles. Methods. Seven professional road cyclists and seven elite kayak paddlers volunteered to participate in this study. Each completed two bouts of constant-load “square-wave” rest-to-exercise transition cycling and arm-cranking exercise at a power output 50–60% of the mode-specific VO2peak presented in a randomized order. Results. In the cyclists, the mean response time (MRT) as well as the phase II VO2 time constant () was significantly slower in the untrained compared with the trained muscles. The opposite was the case in the kayakers. With respect to the relatively untrained muscle groups, while both demonstrated faster VO2 kinetics than normal (moderately fit) subjects, the kayakers evidenced faster VO2 kinetics than the cyclists. This suggests that there is a greater stabilizing-counterforce involvement of the legs in the task of kayaking than of the arms for cycling. Conclusions. The results of the present study provide no support for the “transfer” of a training effect onto the VO2 on-transient response for moderate exercise, but rather support earlier reports demonstrating that peripheral effects may be important in dictating this kinetics.