The Relationship between VO2 and Muscle Deoxygenation Kinetics and Upper Body Repeated Sprint Performance in Trained Judokas and Healthy Individuals

The present study sought to investigate if faster upper body oxygen uptake (VO2) and hemoglobin/myoglobin deoxygenation ([HHb]) kinetics during heavy intensity exercise were associated with a greater upper body repeated-sprint ability (RSA) performance in a group of judokas and in a group of individuals of heterogenous fitness level. Eight judokas (JT) and seven untrained healthy participants (UT) completed an incremental step test, two heavy intensity square-wave transitions and an upper body RSA test consisting of four 15 s sprints, with 45 s rest, from which the experimental data were obtained. In the JT group, VO2 kinetics, [HHb] kinetics and the parameters determined in the incremental test were not associated with RSA. However, when the two groups were combined, the amplitude of the primary phase VO2 and [HHb] was positively associated with the accumulated work in the four sprints (ΣWork). Additionally, maximal aerobic power (MAP), peak VO2 and the first ventilatory threshold (VT1) showed a positive correlation with ΣWork and an inverse correlation with the decrease in peak power output (Dec-PPO) between the first and fourth sprints. Faster VO2 and [HHb] kinetics do not seem to be associated with an increased upper body RSA in JT. However, other variables of aerobic fitness seem to be associated with an increased upper body RSA performance in a group of individuals with heterogeneous fitness level.

Drop jumps versus sled towing and their effects on repeated sprint ability in young basketball players

Background The aim of the investigation was to compare the occurrence of post-activation performance enhancement (PAPE) after drop jumps, or heavy sled towing, and the subsequent effect on repeated sprint ability (RSA). Methods Ten young basketball players (17 ± 1 yrs) performed, in randomized order, RSA test with changes of direction after a standardized warm up followed by drop jumps, heavy sled towing, or no exercise (control condition). Neuromuscular assessments composed of two maximal voluntary contractions of the knee extensors, peripheral nerve stimulation, and surface electromyography (EMG), responses were recorded before and immediately after the RSA. The EMG signal of leg muscles during sprinting were also recorded as well as the blood lactate concentration. Results The drop jumps improved the RSA mean time (P = 0.033), total time (P = 0.031), and slowest time (P = 0.029) compared to control condition, while heavy sled towing did not change RSA outcomes (P > 0.05). All conditions exhibited a decrease of doublet high frequency stimulation force (pre-post measurement) (P = 0.023) and voluntary activation (P = 0.041), evidencing the occurrence from peripheral and central components of fatigue after RSA, respectively, but no difference was evident between-conditions. There was a significantly greater EMG activity during sprints for the biceps femoris after drop jumps, only when compared to control condition (P = 0.013). Conclusion Repeated drop jumps were effective to induce PAPE in the form of RSA, while heavy sled towing had no effect on RSA performance in young basketball players. Furthermore, both conditioning activities exhibited similar levels of fatigue following the RSA protocol. Thus, drop jumps may be used as an alternative to induce PAPE and thus improve performance during sprints in young male basketball players.

On-Field Tests for Patients After Anterior Cruciate Ligament Reconstruction: A Scoping Review

Background: After anterior cruciate ligament reconstruction (ACLR), a patient’s physical capacities, such as (repeated) sprint performance, agility performance, and intermittent endurance performance, are often reduced because of detraining effects. Monitoring the progression of these physical capacities is essential for specific training goals before patients return to complex team sports. Purpose: To map the existing literature regarding on-field tests for (repeated) sprint performance, agility performance, and intermittent endurance performance in patients after ACLR. Study Design: Scoping review; Level of evidence, 4. Methods: A search was performed in 4 electronic databases, PubMed, Embase, CINAHL, and PsycInfo, following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for scoping reviews. Results: There were 11 studies that met the inclusion criteria and described a total of 14 on-field tests for patients after ACLR. Overall, 2 tests were described for sprint performance, 11 tests were related to agility performance, and 1 test was performed for intermittent endurance performance. Conclusion: The results of this scoping review provide an overview of on-field tests to monitor sport-specific progression and to set performance-specific training goals for patients after ACLR before returning to complex team sports.

Relationships between Strength and Step Frequency with Fatigue Index in Repeated Sprint Ability

Force−velocity profile (FVP) and repeated-sprint ability (RSA) tests are indicators of physical capacities in most team sport players. The purpose of this study was to examine the stride kinematics during a repeated-sprint ability (RSA) test and to analyze the relationship between Bosco’s force−velocity profile (FVP) and RSA performance in elite female field hockey players. Thirteen elite-female players performed both RSA (six 30 m maximal sprints) and jumping (CMJ weighted and body weight) tests. Sprinting time fatigue indexes during a 30 m RSA test were correlated with step frequency fatigue indexes (r > 0.7; p < 0.01). CMJ50 showed a large relationship with sprint time fatigue indexes. FV50 showed a very large relationship with sprint time fatigue indexes (r > 0.7; p < 0.01), and a large relationship with the step frequency fatigue indexes (r > 0.5; p < 0.05). This study highlighted two possible ways to improve fatigue indexes in RSA, with the aim of maximizing the distances covered at high-intensities during the matches: (a) strength training and (b) focusing on step frequency during speed training.

Effects of contrast strength training with elastic band program on sprint, jump, strength, balance and repeated change of direction in young female handball players

Maximal strength, power and his derivates (sprint, change of direction repeatedly and jump) are considered as major determinants of success in elite handball players. Contrast strength training with elastic band (CSTEB) program is form of resistance training, and may play an important method of training to improve this quality. This study examined the effects of 10-week contrast strength training with elastic band (CSTEB) program on physical performance in young female handball players. Thirty participants (age: 15.7 ± 0.3 years; body mass: 63.7 ± 3.7 kg; body height: 166.8 ± 3.8 cm; body fat: 26.9 ± 3.4; and Maturity-offset: 2.9 ± 0.3 years) were randomly assigned between experimental group (EG; n = 15) and control group (CG; n = 15). Two-way analyses of variance (group × time) were assessed for handgrip; back extensor; medicine ball throw; 30-m sprint times; Modified Illinois change-of-direction (Illinois-MT); four jump tests [(squat jump (SJ), countermovement jump (CMJ), countermovement jump with arms (CMJA) and five jump test (5JT)]; static (stork) and dynamic (Y balance) balance tests; and repeated sprint T-test (RSTT). The EG enhanced all strength performance [handgrip right, handgrip left, back extensor strength and medicine ball throw (p < 0.001)] compared to CG. The EG enhanced all sprint performance. The EG also improved performance in the Illinois-MT. All jump performance improved significantly [SJ (p = 0.007), CMJ (p = 0.001) and CMJA (p = 0.001)] except 5JT in the EG. Of the same, 3 of 4 repeated sprint T-test scores [RSTT-Best-Time, RSTT-Mean-Time and RSTT-Total-Time] increased significantly in the EG relative to the CG. Conversely, there were no significant changes in balance performance between groups. It is concluded that 10-weeks of CSTEB improved physical performance (strength, sprint, change of direction, jump, and repeated change of direction) measures in young female handball players.