Effects of Two Modalities of Whole-body Electrostimulation Programs and Resistance Circuit Training on Strength and Power.

The main purpose of this study was to compare the effects on strength and muscle power of a training program based on two different modalities of whole-body electrostimulation (WB-EMS) with respect to a resistance-training program aimed at improving dynamic strength. Twenty-two subjects participated in this study: Thirteen male (age 25.2±2.8 years; height 1.78±0.1 m; body mass 72.8±6.4 kg; body fat 11.6±2.3%) and nine female (age 28.2±3.5 years; height 1.63±0.05 m; body mass 56.8±7.6 kg; body fat 19.1±4.7%). Participants were randomly assigned to three groups that underwent three different 6-week training programs: two modalities of WB-EMS, based on different electrical parameters (experimental), and circuit training with overloads (control). Force-velocity curves were calculated for each participant before and after treatment. All groups improved their level of strength and muscle power (paired sample t-Test, p<0.01; d>1) with a similar magnitude. No significant differences were observed between groups (two-way 2×3 Anova, p>0.05) at the end of the experimentation. This study suggests that WB-EMS might be considered as a valid and faster alternative - or an important complementary procedure - to a traditional overload-based resistance-training program for the development of the DS.

Ecological Validity and Reliability of an Age-Adapted Endurance Field Test in Young Male Soccer Players.

Castagna, C, Krustrup, P, D'Ottavio, S, Pollastro, C, Bernardini, A, and Araújo Póvoas, SC. Ecological validity and reliability of an age-adapted endurance field test in young male soccer players. J Strength Cond Res 33(12): 3400-3405, 2019-The purpose of this study was to examine the reliability and the association with relevant match activities (ecological validity) of an age-adapted field test for intermittent high-intensity endurance known as Yo-Yo intermittent recovery level 1 children's test (YYIR1C) in young male soccer players. Twenty-eight young male outfield soccer players (age 11.1 ± 0.9 years, height 142 ± 4.4 cm, body mass 37.0 ± 5.9 kg) with at least 2 years of experience in soccer competitions were tested twice using YYIR1C and an age-adapted competitive small-sided game (i.e., 9v9), 7 days apart in a random order. The YYIR1C performance showed an excellent relative (intraclass correlation coefficient = 0.94) and a good absolute reliability (typical error of measurement as percentage of the coefficient of variation = 5.1%). Very large and significant associations were found between YYIR1C performance and match high-intensity activity (r = 0.53). Large correlations were found between YYIR1C and match sprinting (r = 0.42) and high-intensity metabolic power (r = 0.46) distances. Match total distance was largely associated with YYIR1C (r = 0.30). The results of this study showed that YYIR1C may be considered a valid and reliable field test for assessing intermittent high-intensity endurance in young male soccer players. Because of the relevance of aerobic fitness in youth soccer, future studies testing the sensitiveness of YYIR1C are necessary.

Aerobic Fitness in Top-Class Soccer Referees.

Castagna, C, Bizzini, M, Araújo Póvoas, SC, Schenk, K, Büsser, G, and D'Ottavio, S. Aerobic fitness in top-class soccer referees. J Strength Cond Res 33(11): 3098-3104, 2019-The aim of this study was to examine the aerobic fitness status of top-class male soccer officials using a cross-sectional design and known population group constructs. Fifty-two field referees (FRs, age 38.4 ± 3.3 years; height 181 ± 5.6 cm; body mass 76.8 ± 6.8 kg; body mass index [BMI] 23.4 ± 1.7 kg·m; body fat 20.4 ± 3.6%; and international refereeing experience 5 ± 3.5 years) and 104 assistant referees (ARs, age 37.8 ± 4.1 years; height 176.9 ± 7.5 cm; body mass 72.1 ± 7.4 kg; BMI 23 ± 1.6 kg·m; body fat 19.2 ± 3.6%; and international refereeing experience 7 ± 3.8 years) from 53 National Football Associations worldwide, and candidates of the preliminary open-list developed by the FIFA Refereeing Department for the 2014 World Cup Final Tournament, were tested for aerobic fitness in laboratory conditions with a progressive speed treadmill test to exhaustion. Large (+8.54%, d = 0.8) and small (+3.1%, d = 0.3) differences in absolute (L·min) and relative (ml·kg·min) VO2max were found between FR and AR, respectively. Trivial differences (d = 0.07) were shown in running economy (RE) (6 minutes at 8 km·h) between AR and FR. Using the scaling notation (b = 0.64), medium and significant differences were found between match officials for VO2max and RE (FR > AR; d = 0.6 and 0.67, respectively). Using receiver operating characteristic curve statistics, cutoff values of 3.93 L·min and 50.6 ml·kg·min were detected in absolute and relative VO2max for the FR and the AR (FR > AR), respectively. The FR showed superior aerobic fitness compared with AR. Training prescription should consider intensities at anaerobic threshold speed (14 km·h, 91% heart rate max) when aerobic fitness development is the aim in elite officials.

Reliability Characteristics and Applicability of a Repeated Sprint Ability Test in Young Male Soccer Players.

Castagna, C, Lorenzo, F, Krustrup, P, Fernandes-da-Silva, J, Póvoas, SCA, Bernardini, A, and D'Ottavio, S. Reliability characteristics and applicability of a repeated sprint ability test in young male soccer players. J Strength Cond Res 32(6): 1538-1544, 2018-The aim of this study was to examine the usefulness and reliability characteristics of a repeated sprint ability test considering 5 line sprints of 30 m interspersed with 30 seconds of active recovery in nonelite, outfield, young, male soccer players. Twenty-six (age, 14.9 ± 1.2 years; height, 1.72 ± 0.12 cm; body mass, 62.2 ± 5.1 kg) players were tested 48 hours and 7 days apart for 5 × 30-m performance over 5 trials (T1-T5). Short-term (T1-T2) and long-term (T1-T3-T4-T5) reliabilities were assessed with intraclass correlation coefficient (ICC) and with typical error for measurement (TEM). Short- and long-term reliability ICCs and TEMs for total sprint time and best sprint performance were nearly perfect and satisfactory, respectively. Usefulness (as smallest worthwhile change and TEM ratio) resulted acceptable (i.e., = 1) and good (i.e., >1) for total sprint time and best sprint performance, respectively. The present study revealed that the 5 × 30-m sprint test is a reliable field test in short and long terms when the sum of sprint times and the best sprint performance are considered as outcome variables. Sprint performance decrements variables showed large variability across trials.

Sex Differences in Aerobic Fitness in Top-Class Soccer Referees.

Castagna, C, Bizzini, M, D'Ottavio, S, and Araújo Póvoas, SC. Sex differences in aerobic fitness in top-class soccer referees. J Strength Cond Res 32(11): 3216-3221, 2018-The aim of this study was to assess the aerobic-fitness differences between male and female top-class soccer field referees (FRs). This with the purpose to provide cutoff values useful for training prescription in female FRs. Forty female top-class FRs (age 34.18 ± 3.50 years and 5 ± 3.9 years international refereeing experience) and 52 male FRs (age 38.4 ± 3.3 years and 5 ± 3.5 years international refereeing experience) candidates in the preliminary open list developed by the FIFA Refereeing Department for the 2014 and 2015 World Cup Tournaments, participated in the study. The FRs were tested for aerobic fitness under laboratory conditions with a progressive speed treadmill test until exhaustion. Female FRs showed to possess, on average, lower (large effect) levels of aerobic fitness and performance compared with their male counterparts. The female FRs' V[Combining Dot Above]O2max (48.1 ± 4.4 ml·kg·min) was 7% (large effect) lower than the male FRs (51.9 ml·kg·min). Peak treadmill speed was 11% lower (large effect) in female FRs (16.27 ± 0.94 vs. 14.64 ± 0.96 km·h). The receiver operating characteristic curve analysis enabled cutoff values (47.8 ml·kg·min for V[Combining Dot Above]O2max) that may be used as preliminary cues to guide physiological selection and training prescription in female FRs aiming to officiate male-soccer matches. Only 2.5% of the female FRs showed V[Combining Dot Above]O2max higher than the mean values of male FRs when using the scaled notation (0.68). Female FRs aiming to officiate male competitions should consider training intensities at anaerobic threshold speed (13 km·h, 95% heart rate max) when developing aerobic fitness. Given the very large sex differences in aerobic performance, strength/power training should be proposed to perspective female top-class FRs.

Uphill racewalking at iso-efficiency speed.

The aim of this study was to investigate the effects of gradients (0, 2, and 7%) on biomechanical parameters during racewalking (RW) at iso-efficiency speed (IES). During the experiment, 12 high-level athletes performed at IES on different slopes. The parameters studied were surface muscular activity (EMG) of 5 muscles of the leg using Muscle Lab (Boscosystem); kinematic parameters were collected using a high-speed camera (210 Hz) analyzed with Dartfish 5.5 Pro; and heart rate (HR) was monitored with a Cardio Polar. The results showed step length (SL), step frequency (SF), and internal work (WINT) decreased with increased treadmill gradient: SL = ([0-2% = 3.48%, p = 0.158], [0-7% = 12.17%, p < 0.001]); SF = ([0-2% = 2.38%, p = 0.173], [0-7% = 6.07%, p < 0.01]); WINT = ([0-2% = 8.34%, p < 0.001], [0-7% = 22.81%, p < 0.0001]). Conversely, contact time (CT) and HR increased less significantly with the increased gradients: CT = ([0-2% = 2.46%, p = 0.198], [0-7% = 6.56%, p < 0.01]); HR = ([0-2% = 0.62%, p = 0.652], [0-7% = 3.25%, p < 0.05]). The knee angle (KE) increased, whereas ankle angle (AK) and hip angle (HP) decreased with the increased gradients: AK = ([0-2% = 1.69%, p < 0.001], [0-7% = 1.13%, p < 0.01]); HP = ([0-2% = 0.22%, p < 0.03], [0-7% = 0.16%, p = 0.456]); KE = ([0-2% = 1.01%, p < 0.001], [0-7% = 1.60%, p < 0.001]). Electromyography (EMG) significantly decreased with the increased gradients in the: tibialis anterior ([0-2% = 22.49%, p < 0.0001], [0-7% = 41.18%, p < 0.0001]) and rectus femoris ([0-2% = 15.35%, p < 0.0001], [0-7% = 29.13%, p< 0.0001]). In contrast, EMG activity was significantly increased in the vastus lateralis ([0-2% = 22.95%, p < 0.0001], [0-7% = 31.15%, p < 0.0001]), gastrocnemius medialis ([0-2% = 21.40%, p < 0.001], [0-7% = 48.37%, p < 0.0001]), and biceps femoris ([0-2% = 190.78%, p < 0.0001], [0-7% = 201.37%, p < 0.0001]). The results indicate that increasing the gradient to 2% did not elicit an increased HR in racewalkers; however, at a 7% gradient, greater muscle activity was required.

Footstep analysis at different slopes and speeds in elite race walking.

In order to investigate the effects of speed and slope on kinematic parameters, we studied the step parameters of 12 elite race walkers on a treadmill at different speeds (3.61, 3.89, and 4.17 m·s(-1)) and slopes (0, 2, and 7%). A high-speed digital camera (210 Hz) was used to record motion, and 2D data were analyzed with Dartfish 5.5Pro. The parameters studied were step length (SL), step frequency (SF), and contact time (CT). The results showed that the increases in SL were linearly related to increases in speed: r = 0.37 with p < 0.01, whereas decreases in SL were elicited with an increase in slope r = -0.56, p < 0.0001 ([0-2% = -3.5%, p < 0.02], [0-7% = -7.5%, p < 0.01]). The SF was positively correlated with increases in speed, r = 0.56, p = 0.0001, and slopes, r = 0.50, p < 0.0001 (0-2% = 3.6% n.s.; 0-7% = 8.5%, p < 0.01). Conversely, CT was negatively correlated with increases of both speed; r = -0.57, p < 0.0001 and slope r = -0.50, p < 0.0001 (0-2% = -3.4%, n.s.; 0-7% = -7.7%, p < 0.01). These results suggest that using slopes <7% could considerably alter the neuromechanical behavior of athletes, whereas slopes around 2% could positively influence the performance of the elite race walkers without altering the race-walking technique.

Kinematics of running at different slopes and speeds.

The aim of this study was to verify the influence of the combination of different running speeds and slopes based on main kinematic parameters in both groups of elite (RE) and amateur (RA) marathon runners. All subjects performed various tests on a treadmill at 0, 2, and 7% slopes at different speeds: 3.89, 4.17, 4.44, 4.72, and 5.00 m·s. A high speed digital camera, 210 Hz, has been used to record; Dartfish 5.5Pro has been used to perform a 2D video analysis. Step length (SL), step frequency (SF), flight time (FT), and contact time (CT) were determined and used for comparison. SL, SF, and FT parameters increased, and CT parameter decreased as speed increased. As slopes increased, SL and FT decreased and SF increased in both groups and only CT decreased in RE, whereas in RA, it increased. Data were fitted to the linear regression line (R > 0.95). The 2 groups were significantly different (p < 0.05) in FT, SL, and SF at all speeds in level running. A significant difference between the 2 groups was found in FT at 2 and 7% slopes at all speeds (p < 0.05). Percentage alterations in all variables were greater in the RA group. In conclusion, the choice of optimum SL and SF, through efficient running can be maintained, is influenced not only by speed but also by slopes. Elite runners perform more efficiently than amateur runners who have less experience.