Validity of the Modified Conconi Running Test

Biomechanical, physiological and anthropometrical predictors of performance in recreational runners

Background

The maximal running speed (VMAX) determined on a graded treadmill test is well-recognized as a running performance predictor. However, few studies have assessed the variables that predict VMAX in recreationally active runners.

Methods

We used a mathematical procedure combining Fick's law and metabolic cost analysis to verify the relation between (1) VMAX versus anthropometric and physiological determinants of running performance and, (2) theoretical metabolic cost versus running biomechanical parameters. Linear multiple regression and bivariate correlation were applied. We aimed to verify the biomechanical, physiological, and anthropometrical determinants of VMAX in recreationally active runners. Fifteen recreationally active runners participated in this observational study. A Conconi and a stead-steady running test were applied using a heart rate monitor and a simple video camera to register the physiological and mechanical variables, respectively.

Results

Statistical analysis revealed that the speed at the second ventilatory threshold, theoretical metabolic cost, and fat-mass percentage confidently estimated the individual running performance as follows: VMAX = 58.632 + (-0.183 * fat percentage) + (-0.507 * heart rate percentage at second ventilatory threshold) + (7.959 * theoretical metabolic cost) (R2 = 0.62, p = 0.011, RMSE = 1.50 km.h-1). Likewise, the theoretical metabolic cost was significantly explained (R2 = 0.91, p = 0.004, RMSE = 0.013 a.u.) by the running spatiotemporal and elastic-related parameters (contact and aerial times, stride length and frequency, and vertical oscillation) as follows: theoretical metabolic cost = 10.421 + (4.282 * contact time) + (-3.795 * aerial time) + (-2.422 * stride length) + (-1.711 * stride frequency) + (0.107 * vertical oscillation).

Conclusion

Critical determinants of elastic mechanism, such as maximal vertical force and vertical and leg stiffness were unrelated to the metabolic economy. VMAX, a valuable marker of running performance, and its physiological and biomechanical determinants can be effectively evaluated using a heart rate monitor, treadmill, and a digital camera, which can be used in the design of training programs to recreationally active runners.

Agreement between heart rate deflection point and maximal lactate steady state in young adults with different body masses

We examined the agreement between heart rate deflection point (HRDP) variables with maximal lactate steady state (MLSS) in a sample of young males categorized to different body mass statuses using body mass index (BMI) cut-off points. One hundred and eighteen young males (19.9 ± 4.4 years) underwent a standard running incremental protocol with individualized speed increment between 0.3 and 1.0 km/h for HRDP determination. HRDP was determined using the modified Dmax method called S.Dmax. MLSS was determined using 2-5 series of constant-speed treadmill runs. Heart rate (HR) and blood lactate concentration (La) were measured in all tests. MLSS was defined as the maximal running speed yielding a La increase of less than 1 mmol/L during the last 20 min. Good agreement was observed between HRDP and MLSS for HR for all participants (±1.96; 95% CI = -11.5 to +9.2 b/min, ICC = 0.88; P < 0.001). Good agreement was observed between HRDP and MLSS for speed for all participants (±1.96; 95% CI = -0.40 to +0.42 km/h, ICC = 0.98; P < 0.001). The same findings were observed when participants were categorized in different body mass groups. In conclusion, HRDP can be used as a simple, non-invasive and time-efficient method to objectively determine submaximal aerobic performance in nonathletic young adult men with varying body mass status, according to the chosen standards for HRDP determination.

Reliability of Lactate Scout Portable Analyzer in Agility Dogs During Multiple Measurements

The aim of this study was to evaluate the reliability of multiple measurements with Lactate Scout portable analyzer in dogs during treadmill exercise. Ten Border collies were involved in the study and blood samples were taken before, three times during and twice after the treadmill exercise. Lactate concentration was measured in duplicate, by Scout portable analyzer and the reference biochemical analyzer in the laboratory, and the obtained values were compared. There was a high and positive correlation between these two methods (r=0.96, p=0.003). The Lactate Scout analyzer reveals a high degree of agreement with the laboratory method and therefore can be valid for use in research of veterinary sports medicine and emergency veterinary medicine where multiple measurements of lactate concentrations are often needed.

Heart rate deflection point during incremental test in competitive agility border collies

The aim of this study was to determine a heart rate deflection point (HRdp) in competitive agility dogs. Fourteen healthy border collies underwent progressive incremental treadmill exercise--modified Conconi test protocol. Heart rate was continuously recorded, and the HRdp was estimated using two methods: subjective and computer aided regression. Maximal heart rate (HRmax), achieved running speed at the anaerobic threshold and at the end of test were also determined. Statistical analysis showed a very high positive correlation between HRdp determined by two methods. The mean HRdp in this research corresponded to 80% of HRmax. The wide range of individual HRdp (162-229 BPM) indicates the need of an individual approach in assessing physiological parameters. To the authors' knowledge, this is the first application of Conconi modified test for estimating anaerobic threshold in agility dogs since the standard for dogs is yet undetermined. Future studies need to detect the most appropriate and reliable technique for its determination as well as its applicability in programming of the optimal training intensity.

Strong relationship between heart rate deflection point and ventilatory threshold in trained rowers

The purpose of this study was to assess the relationship between heart rate deflection point (HRDP) and ventilatory threshold (VT) to the physiological and performance variables in a relatively large group of trained men rowers. We proposed the hypothesis that physiological and performance variables corresponding to HRDP are not significantly different from corresponding variables at VT, which would justify the use of HRDP as a simple, affordable, and noninvasive method of anaerobic threshold assessment in trained rowers. Eighty-nine trained men rowers (mean ± SD: age 21.2 ± 4.1 years; stature 1.89 ± 0.06 m; body mass 89.2 ± 8.4 kg; VO₂max [maximum oxygen uptake] 5.39 ± 0.62 L/min⁻¹) completed an incremental rowing ergometer exercise test to exhaustion. Three independent, experienced observers determined both HRDP and VT. HRDP was determined by visual and computer-aided regression analyses and was evident in all rowers. The main findings include (a) there is a strong relationship among all observed physiological and performance variables corresponding to HR(HRDP) and HR(VT) (r = 0.79-0.96; p < 0.001) and (b) power output, oxygen uptake, ventilation, tidal volume and breathing rate corresponding to HR(HRDP) and HR(VT) were not significantly different (p ≥ 0.011), whereas HR(HRDP) was slightly but significantly higher than HR(VT) (174.5 vs. 172.8 beats·min⁻¹; p = 0.003). The standard error of the estimate in predicting the HR(VT) based on HR(HRDP) was 5.1 beats·min⁻¹. The subsequent data suggest that, in general, trained rowers may be able to periodically assess their aerobic endurance and evaluate the effects of training programs using the HRDP method.