Effects of Sprint Interval Training With Active Recovery vs. Endurance Training on Aerobic and Anaerobic Power, Muscular Strength, and Sprint Ability

The Addition of Sprint Interval Training to Field Lacrosse Training Increases Rate of Torque Development and Contractile Impulse in Female High School Field Lacrosse Players

Field lacrosse requires sudden directional changes and rapid acceleration/deceleration. The capacity to perform these skills is dependent on explosive muscle force production. Limited research exists on the potential of sprint interval training (SIT) to impact explosive muscle force production in field lacrosse players. The purpose of this study is to examine SIT, concurrent to field-lacrosse-specific training, on the rate of torque development (RTD), contractile impulse, and muscle function in female high school field lacrosse players (n = 12; 16 ± 1 yrs.). SIT was performed three times per week, concurrent to field-lacrosse-specific training, for 12 weeks. Right lower-limb muscle performance was assessed pre-, mid-, and post-SIT training via isometric and isokinetic concentric knee extensor contractions. Outcomes included RTD (Nm·s^-1), contractile impulse (Nm·s), and peak torque (Nm). RTD for the first 50 ms of contraction improved by 42% by midseason and remained elevated at postseason (p = 0.004, effect size (ES) = -577.3 to 66.5). Contractile impulse demonstrated a training effect across 0-50 ms (42%, p = 0.004, ES = -1.4 to 0.4), 0-100 ms (33%, p = 0.018, ES = 3.1 to 0.9), and 0-200 ms (22%, p = 0.031, ES = -7.8 to 1.6). Isometric (0 rad·s^-1) and concentric (3.1 rad·s^-1) strength increased by 20% (p = 0.002, ES = -60.8 to -20.8) and 9% (p = 0.038, ES = -18.2 to 0.0) from SIT and field-lacrosse-specific training, respectively (p < 0.05). SIT, concurrent to field-lacrosse-specific training, enhanced lower-limb skeletal muscle performance, which may enable greater sport-specific gains.

Repeated sprint ability in young football players according to the position and formation of the team: the effect of a specific training program

BACKGROUND

The aim of this study was to investigate the effect of a specific training program for 12-weeks (twice a week) on the repeated sprint ability (RSA), according to the position of the football player in the formation of the team.

METHODS

Two groups of U-17 football players (experimental-group, N.=22 and control-group, N.=19) and five positions (central-defenders, wide-defenders, central-midfielders, wingers, and central-attackers) according to the position in the formation (1-4-3-3) were studied. Sexual maturation was classified according to Tanner's stages. RSA and isokinetic strength were measured pre- and after the training program.

RESULTS

The results showed that in RSA were differences in the factor time in the best (F=9.316, η²=0.383, P=0.008) and mean time (F=8.002, η²=0.348, P=0.013), but there were no differences between the groups. In strength, differences were observed in the time, mostly in the extensors at the three angular velocities (60°, 180°, 300°·sec^-1) with differences in the group only in the maximum force (F=8.090, η²=0.366, P=0.013). No differences between players' positions were observed.

CONCLUSIONS

A specific training program seems to affect players' performance on repeated sprint ability and the specific training in the players' position according to the team formation has a positive effect on the muscle power of football players.

Effects of Mobile-Based Rehabilitation in Adolescent Football Players with Recurrent Lateral Ankle Sprains during the COVID-19 Pandemic

Football is a sport involving dynamic movements, and ankle sprains are common sports injuries experienced by football players. Ankle sprains exhibit a high recurrence rate, and rehabilitation training is effective; however, expert-supervised rehabilitation (SVR) at training centers is difficult due to the recent COVID-19 pandemic. This study investigated the effects of mobile-based rehabilitation (MBR) performed at home by high school football players. Sixty players (SVR: 30 and MBR: 30) with recurrent ankle sprains were analyzed. The rehabilitation program consisted of strength and balance training, and the training intensity was gradually increased from week 1 to week 8. The SVR group underwent training at the center with experts, and the BMR group were provided with programs and feedback using mobile devices. Ankle muscle strength was evaluated by measuring isometric eversion, inversion, plantarflexion, and dorsiflexion contraction using a hand-held dynamometer, and dynamic balance was assessed using the Y-balance test (YBT; anterior, posteromedial, and posterolateral); the Foot and Ankle Outcome Score (FAOS) was used for the subjective evaluation. Measurements were conducted at weeks 1, 4, and 8. The patients visited the clinic within 1 week after the injury, and the first test was conducted after consent to participate in the research. Patients underwent the second test at an average of 3.2 weeks after the first test, and the last test at an average of 4.4 weeks after the second test. Although only the SVR group exhibited improvement in strength (eversion and dorsiflexion), YBT and subjective satisfaction at week 4, these measurements improved in both the SVR and MBR groups at week 8. Therefore, mobile–based rehabilitation could be a suitable alternative for high school athletes with ankle sprains who cannot undergo supervised rehabilitation.

Effects of sprint interval training on sloping surfaces on aerobic and anaerobic power

Study aim: Several sprint interval training applications with different slope angles in the literature mostly focused on sprint running time and kinematic and dynamic properties of running. There is a lack of comparative studies investigating aerobic and anaerobic power. Therefore, this study aimed to examine the effects of sprint interval training on sloping surfaces on anaerobic and aerobic power.

Material and methods: A total of 34 male recreationally active men aged 20.26 ± 1.68 years and having a BMI of 21.77 ± 1.74 were assigned to one of the five groups as control (CON), uphill training (EXP 1 ), downhill training (EXP 2 ), uphill + downhill training (EXP 3 ) and horizontal running training (EXP 4 ) groups. Gradually increased sprint interval training was performed on horizontal and sloping surfaces with an angle of 4°. The training period continued for three days a week for eight weeks. The initial and the final aerobic power was measured by an oxygen analyser and anaerobic power was calculated from the results of the Margaria-Kalamen staircase test.

Results: Following the training programme, an increase in aerobic power was found in all training groups (EXP 1 = 20.79%, EXP 2 = 14.95%, EXP 3 = 26.85%, p < 0.01) and EXP 4 = 20.46%) (p < 0.05) in comparison with the CON group (0.12%), but there were no differences among the training groups. However, significant increases in anaerobic power were found in uphill training (4.91%) and uphill + downhill training (8.35%) groups (p < 0.05).

Conclusion: This study showed that all sprint interval studies on horizontal and sloping surfaces have a positive effect on aerobic power, and uphill and combined training are the most effective methods for the improvement of anaerobic power.

Acute effects of very low-volume high-intensity interval training on muscular fatigue and serum testosterone level vary according to age and training status

PURPOSE

To compare the acute physiological responses of three different very low-volume cycling sessions (6 × 5 s, 3 × 30 s, and 3 × 60 s) and their dependence on age and training status.

METHODS

Subjects were untrained young men (mean ± SD; age 22.3 ± 4.6 years, VO₂peak 42.4 ± 5.5 ml/kg/min, n = 10), older untrained men (69.9 ± 6.3 years, 26.5 ± 7.6 ml/kg/min, n = 11), and endurance-trained cyclists (26.4 ± 9.4 years, 55.4 ± 6.6 ml/kg/min, n = 10). Maximal voluntary contraction (MVC) and electrically stimulated knee extension torque, and low-frequency fatigue, as ratio of stimulation torques at 20-100 Hz (P20/100), were measured only 24 h after exercise. Serum testosterone (Te) and blood lactate concentrations were measured only 1 h after exercise.

RESULTS

All protocols increased the blood lactate concentration and decreased MVC and P20/100 in young men, but especially young untrained men. In old untrained men, 6 × 5 s decreased P20/100 but not MVC. Te increased after 3 × 30 s and 3 × 60 s in young untrained men and after 3 × 60 s in older untrained men. The increase in Te correlated with responses of blood lactate concentration, MVC, and P20/100 only in old untrained men.

CONCLUSIONS

As little as 6 × 5 s all-out cycling induced fatigue in young and old untrained and endurance-trained cyclists. Slightly higher-volume sessions with longer intervals, however, suppressed contractile function more markedly and also transiently increased serum testosterone concentration in untrained men.