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This study compared the effectiveness of a passing-skill training (PST) concept (theory lectures, passing-skill training, and external- and internal-focus feedback) and three-a-side small-sided games (SSG) on improving side-foot kick accuracy among youth female soccer players. Seventeen youth female soccer players (age: 12.7 ± 0.8 years) completed the pre-post-intervention study, where the pre- and post-tests included three 10-m passing accuracy tests with increasing level of complexity: (1) stationary ball with a fixed target (SBFT), (2) rolling ball with a fixed target (RBFT), and (3) rolling ball with a moving target (RBMT). Based on the pre-tests, the participants were matched into the PST group or the SSG group. The training consisted of nine 30-min sessions for both groups during a period of 4.5 weeks. During the intervention, the PST group significantly improved the side-foot kick accuracy across all three tests. In contrast, the SSG group showed no significant change in passing accuracy in either the RBFT test or the RBMT test; however, their side-foot kick accuracy was significantly reduced in the SBFT test. There were significant between-group differences in side-foot kick accuracy across all three tests after the intervention, where the PST group had a greater side-foot kick accuracy than the SSG group. In conclusion, results indicate that the PST concept significantly enhances passing accuracy across all tested variables, unlike SSG, suggesting PST's superiority in technical skill development.

The aim of the study was to compare the oxygen uptake (V˙O2 ), heart rate (HR), rated perceived exertion (RPE), and blood-lactate concentration (BLa) in a conventional anaerobic-threshold test at constant speed intervals with running at the same mean speeds, but with speed variations similar to a football match. Nine male football players completed two test days with two treadmill running tests: a submaximal test followed by a maximal test. The submaximal tests (tests A and B) comprised five stages of five minutes each, with between 8–16 km·h−1 mean speeds. The speed was constant for test A, whereas in test B, the speed during the stages varied every 15 seconds. Mean values of V˙O2 , HR, BLa, and RPE for the legs (RPElegs) and ventilation (RPEvent) were determined for each stage. No significant differences between tests A and B were found for V ˙O2 , HR, and RPElegs. The BLa was significantly higher for test B at mean speeds of 10, 14, and 16 km·h−1. RPEvent did not differ between tests for any work intensity, except for a higher rating for test A at 8 km·h−1. The equal HR and V ˙O2 responses for the anaerobic-threshold tests with constant and varying speeds suggests that male football players’ aerobic energy expenditure during match could be estimated based on HR recordings. The significant difference in BLa between constant and varying speeds indicates the need to use anaerobic-threshold tests with varying speeds in football. 

This study investigated whether repeated transitions between seated and standing positions has a different physiological response compared to continuous use of either seated position or standing position during steep uphill cycling among elite cyclists. Ten elite male cyclists completed three 5-min treadmill cycling tests at an inclination of 6.8° with constant individual-based speed resulting in a work intensity close to the aerobic threshold. During the first and third test, the participants used standing position (ST test) and seated position (SE test) or vice versa, whereas in the second test, they made repeated transitions between standing and seated positions every 10 s (RT test). The last 2 min of each test was used to measure the mean values of oxygen uptake (V̇O2) and respiratory exchange ratio, which were used to calculate the metabolic rate (MR) and gross efficiency (GE). Additionally, the blood-lactate concentration before and after (Lapost) each test was determined. One-way repeated measures ANOVA was used to determine the effect of cycling position on the physiological response. No significant differences between tests were observed for the variables related to aerobic energy expenditure (i.e., V̇O2, MR and GE), whereas the RT test was associated with a significantly lower Lapost compared to the ST and SE tests. Steep uphill cycling, at an intensity close to the aerobic threshold, with repeated transitions between standing and seated positions, did not have a higher oxygen consumption; instead, the blood-lactate concentration was lower during the RT test compared to that under continuous use of either seated or standing position.

The purpose of the study was to investigate whether there are energy-efficiency differences between the execution of the old-fashioned double-poling technique (DPOLD) and the modern double-poling technique (DPMOD) at a submaximal work intensity among elite male cross-country skiers. Fifteen elite male cross-country skiers completed two 4-min tests at a constant mechanical work rate (MWR) using the DPMOD and DPOLD. During the last minute of each test, the mean oxygen uptake (VO2) and respiratory exchange ratio (RER) were analyzed, from which the metabolic rate (MR) and gross efficiency (GE) were calculated. In addition, the difference between pretest and posttest blood-lactate concentrations (BLadiff) was determined. For each technique, skiers’ joint angles (i.e., heel, ankle, knee, hip, shoulder, and elbow) were analyzed at the highest and lowest positions during the double-poling cycle. Paired-samples t-tests were used to investigate differences between DPMOD and DPOLD outcomes. There were no significant differences in either VO2mean, MR, GE, or BLadiff (all P > 0.05) between the DPMOD and DPOLD tests. DPMOD execution was associated with a higher RER (P < 0.05). Significant technique-specific differences were found in either the highest and/or the lowest position for all six analyzed joint angles (all P < 0.001). Hence, despite decades of double-poling technique development, which is reflected in the significant biomechanical differences between DPOLD and DPMOD execution, at submaximal work intensity, the modern technique is not more energy efficient than the old-fashioned technique. 

Asthma is common in cross-country skiers and is often treated with ß2-agonists and inhaled corticosteroids (ICS). Exhaled nitric oxide is often used to guide ICS treatment in asthma. This study investigated the change in the pulmonary NO dynamics before and after a maximum oxygen uptake (V̇O2-max) test.An extended NO analysis was performed among Swedish elite junior cross-country skiers (n=25), with and without declared asthma, before and after a V̇O2-max test using roller skis. Asthma was declared by six boys and two girls among whom five occasionally used ICS.There were no differences in the baseline NO parameters between those with and without declared asthma. The diffusion capacity over airway wall (DawNO) was 21 (17,25) mL·s−1 (median, quartiles), which is much increased for this age group. After the V̇O2-max test, there were statistically significant differences from the baseline fraction of exhaled nitric oxide (FENO50), NO-flux from airways, DawNO and alveolar NO values; but not in the NO content in airway wall (CawNO) for all subjects together as one group. However, in the asthma group, differences were only seen in the FENO50 and in CawNO.Interestingly, a majority of the subjects had an increase in the DawNO. An increase in DawNO has been found with allergic asthma together with elevated CawNO. The skiers did not have elevated CawNO, which indicates an absence of inflammation in the airway wall. Modelling of lung NO production clearly shows that the asthma among our skiers is distinct from the allergic asthma in non-athletes.

PURPOSE: To investigate the gross efficiency (GE) and delta efficiency (DE) during cycling and running in elite triathletes.

METHODS: Five male and five female elite triathletes completed two incremental treadmill tests with an inclination of 2.5° to determine their GE and DE during cycling and running. The speed increments between the 5-min stages were 2.4 and 0.6 km h^-1 during the cycling and running tests, respectively. For each test, GE was calculated as the ratio between the mechanical work rate (MWR) and the metabolic rate (MR) at an intensity corresponding to a net increase in blood-lactate concentration of 1 mmol l^-1. DE was calculated by dividing the delta increase in MWR by the delta increase in MR for each test. Pearson correlations and paired-sample t tests were used to investigate the relationships and differences, respectively.

RESULTS: There was a correlation between GE_cycle and GE_run (r = 0.66; P = 0.038; R² = 0.44), but the correlation between DE_cycle and DE_run was not statistically significant (r = - 0.045; P = 0.90; R² = 0.0020). There were differences between GE_cycle and GE_run (t = 80.8; P < 0.001) as well as between DE_cycle and DE_run (t = 27.8; P < 0.001).

CONCLUSIONS: Elite triathletes with high GE during running also have high GE during cycling, when exercising at a treadmill inclination of 2.5°. For a moderate uphill incline, elite triathletes are more energy efficient during cycling than during running, independent of work rate.