The aims of this study were to examine sex differences in college students while they performed cardiopulmonary resuscitation (CPR) on a manikin for 20 min in (a) objective and subjective effort indicators and (b) to analyse the influence of potential confounders (age, BMI and cardiorespiratory fitness) on these sex differences. Sixty-three participants were recruited. Participants performed 20 min of CPR on a manikin. During the CPR trial, percentages of maximal heart rate levels were higher in women than in men (P<0.05) and perceived exertion increased significantly in both sexes over time (P=0.05); furthermore, at the last two time points analysed, women scored higher than men (P<0.05). However, these sex differences disappeared when controlling for age, BMI and cardiorespiratory fitness. In conclusion, indicators of exertion during CPR are higher in women than in men, but these sex differences are because of BMI and differences in physical fitness conditions.

Background: The use of normobaric hypoxia can bring benefits to sports performance because it improves haematological parameters and/or physical activity tests. Our objective was to conduct a systematic review so as to analyse the methods used in hypoxia and to detect its effects on middle- and/or long-distance runners. Methods: Research was conducted using five electronic databases (PubMed, SportDiscus, Cochrane Library, Scopus and PEDro) until December 2021. The methodological quality of the included studies was assessed using the PEDro scale. Results: Having analysed 158 studies, 12 were chosen for the qualitative and quantitative synthesis. A significant improvement on time until exhaustion was detected, and oxygen saturation decreased after the intervention. There were no significant changes in the 3000-metre time trial or in the haematocrit percentage. The changes in percentage of reticulocytes, heart rate, maximal heart rate, lactate concentration and erythropoietin were heterogeneous between the different research studies. Conclusion: short exposure (less than 3 h to normobaric hypoxia significantly increases the time to exhaustion). However, longer exposure times are necessary to increase haemoglobin. Altitude and exposure time are highly heterogeneous in the included studies.

Determining oxygen muscle saturation (SmO 2 ) using near-infrared spectroscopy (NIRS) is an emerging technique that is increasingly used in sports science; therefore, it is necessary to know its results in different population groups. We analysed it in a group of recreational participants in Nordic Walking. The purpose of this research was to analyse the SmO 2 values obtained at various times from testing in a group of athletes over 45. Thirty athletes (18 males) with a mean age of 51.3 years completed a maximal exercise testing in treadmill according to a modified Bruce protocol on a ramp. The electrocardiogram was continuously monitored. We measured VO 2 max (Metalyzer 3B). In addition, we placed a Humon Hex device on the right thigh to measure quadriceps oxygenation. Heart rate, VO 2 , and SmO 2 ratios were obtained based on the exercise intensity. We obtained a SmO 2 at startup of 63.3%, standard deviation (SD) 9.2%; SmO 2 declined 61.8%, SD 11.4%; SmO 2 in VO 2 max 57.4% SD 10.2% and SmO 2 5 minutes after starting recovery 72.5% SD7.9%. There was a relationship between ventilatory thresholds and variations in SmO 2 . There were no significant differences between the sexes. We could conclude that the minimum values of SmO 2 were related to the VO 2 max. During the recovery phase, the values were higher than at rest. The information obtained could be used to control and plan the training. KEY WORDS nordic walking, muscle oxygenation, maximal exercise testing ORIGINAL SCIENTIFIC PAPER

Introduction: Near infrared spectroscopy (NIRS) is a non-invasive technique that is used in the assessment of tissue oxygenation and the monitoring of physical activity. Objective: To determine the influence of sexual, anthropometric and ergospirometric factors on muscle oxygenation of the quadriceps and gastrocnemius, obtained by NIRS during a stress test. Methods: Twenty healthy subjects participated in this study (10 women). Two Humon Hex® devices were placed on the dominant side of the quadriceps and gastrocnemius muscles to measure muscle oxygen saturation (SmO2). The stress test was performed on a treadmill with electrocardiographic control and measurement of oxygen consumption. SmO2 was obtained at rest and after maximum effort during the stress test. In addition, the height, weight, skinfold and waist contour were measured. Bioimpedance was used to obtain the percentages of fat mass and muscle mass, which were used to calculate the relative fat mass (RFM). Results: The SmO2 of both muscles at rest is higher in males than in females. At maximum effort, the SmO2 of the quadriceps is similar in both groups. The SmO2 of both muscles is positively related to height, body mass, percentage of mass muscle and waist contour, and negatively with percentage of mass fat, RFM and skinfold thickness. The negative correlation between fat percentage and oxygen saturation is more evident in females. It was observed that the variables that quantify maximum effort are not related to the SmO2 values, except for the correlation between HR max and SmO2 of the gastrocnemius muscle in males. Conclusion: The SmO2 of recreational athletes is influenced by the location of the device and the fat mass of the subjects. The biggest differences between the sexes are in the gastrocnemius muscle. Level of Evidence II; Diagnostic Studies - Investigating a Diagnostic Test .

The Cobb angle value is a critical parameter for evaluating adolescent idiopathic scoliosis (AIS) patients. This study aimed to evaluate a software’s validity and absolute reliability to determine the Cobb angle in AIS digital X-rays, with two different degrees of experienced observers. Four experts and four novice evaluators measured 35 scoliotic curves with the software on three separate occasions, one month apart. The observers re-measured the same radiographic studies on three separate occasions three months later but on conventional X-ray films. The differences between the mean bias errors (MBE) within the experience groups were statistically significant between the experts (software) and novices (manual) (p < 0.001) and between the novices (software) and novices (manual) (p = 0.005). When measured with the software, the intra-group error in the expert group was MBE = 1.71 ± 0.61° and the intraclass correlation coefficient (ICC (2,1)) = 0.986, and in the novice group, MBE = 1.9 ± 0.67° and ICC (2,1) = 0.97. There was almost a perfect concordance among the two measurement methods, ICC (2,1) = 0.998 and minimum detectable change (MCD95) < 0.4°. Control of the intrinsic error sources enabled obtaining inter- and intra-observer MDC95 < 0.5° in the two experience groups and with the two measurement methods. The computer-aided software TraumaMeter increases the validity and reliability of Cobb angle measurements concerning manual measurement.