High-Intensity Interval Training in Well-trained Cyclists : Consecutive Days versus Alternating Days

Purpose: This study compared the effects of 3 weeks of high-intensity interval training (HIT) on well-trained cyclists when three weekly HIT sessions were performed on either consecutive or non-consecutive days. Methods: Fifteen well-trained cyclists volunteered to participate in the study. They performed a 5-km time-trial (TT5k) and an incremental test to assess peak oxygen consumption (VO2peak) and peak aerobic power output (PPOa), and were divided into two matched-pair groups based on TT5k performance. For 3 weeks, one group (N=9) performed three HIT sessions per week on consecutive days, while the other group (N=6) did so on non-consecutive days. Subjects trained lightly or not at all on the remaining 4 days. Sessions for both groups consisted of up to eight 2.5-minute intervals at 100% of PPOa, Pre- and post-training TT5k performance, VO2peak, and PPOa were compared using 2 x 2 (group x time) ANOVA with repeated measures on time. Results: Both groups significantly improved TT5k velocity (0.9 ± 0.8 km·hf -1) and average power output (17 ± 19 W), as well as VO2peak (0.2 ± 0.2 L·min-1), and PPOa (23 ± 15 W). Mean improvement (~7%) was similar for both groups, but varied widely among individuals. Conclusion: Neither the consecutive-day nor the non-consecutive day training design is definitively superior, although individual athletes may respond better to one design or the other

Energy transformation on vault in elite artistic gymnastics: comparisons between simple and difficult Tsukahara and Yurchenko vaults

Performance on vault in artistic gymnastics depends on the difficulty and the execution quality of the performed vault. However, differences of kinetic energy between simple and difficult vaults remain elusive. Therefore, in this study, 48 Tsukahara and Yurchenko vaults, performed by 20 top-level gymnasts, were recorded with 3D-motion capture and the flux of translational (TKE), angular kinetic (AKE), potential (PE), and total energy were calculated and compared. Results revealed that upon initial springboard contact, almost all of the kinetic energy for Tsukahara vaults is comprised of TKE, whereas Yurchenko vaults were characterized by substantially less TKE, but far greater AKE (and similar PE). During springboard contact of Tsukahara vaults, AKE is increased (+70%) and thereafter mostly preserved during push off from the table (−6%). For Yurchenko vaults, AKE is preserved during springboard contact but reduced (−30%) in exchange for PE at push off. During the second flight phase of Yurchenko vaults, total energy was 10% higher than at initial springboard contact (Tsukahara: −1%). For vaults of increasing difficulty, 5.9% more AKE is needed for each additional 180° of longitudinal-axis rotation. This knowledge may help coaches evaluate athletes’ potential and focus training on appropriate physical and/or technical aspects of the vault performance

PILOT STUDY: OPTICAL TRACKING OF BARBELL KINEMATICS FOR LOW-COST STRENGTH TRAINING PERFORMANCE MONITORING

Velocity based training (VBT) is a promising method to quantify and direct resistance training. Recent advances in computer science have opened the way for low-cost methods to measure VBT using video data from a smartphone. This work introduces and analyses the feasibility of a computer vision-based Python application in tracking barbell kinematics during VBT, compared against Vicon data during the back squat in one subject. As input into the algorithm, sagittal-plane video data is needed with the barbell plate in focus. Time of the concentric part of the squat and vertical barbell displacement are then automatically tracked using OpenCV libraries. The time parameter was accurately assessed using two different OpenCv Tracker, the KCF (r=0.83, SEE=0.02s) and the MOSSE (r=0.81, SEE=0.02s) tracker, respectively. For the vertical displacement, a lower accuracy was obtained using KCF (r=0.36, SEE=0.02m) and MOSSE (r=0.62, SEE=0.01m). Tracking errors could be explained by the camera set-up, as well as differences in frame rates between the video and the Vicon data. It might be possible to correct these errors in future work using machine learning techniques. This pilot study shows the feasibility of a computer vision-based Python application to measure barbell kinematics in a low-cost manner and might play a part towards advancing VBT monitoring technologies for widespread use

Simple assessment of height and length of flight in complex gymnastic skills: Validity and reliability of a two-dimensional video analysis software

In artistic gymnastics, the possibility of using 2D video analysis to measure the peak height (hpeak) and length of flight (L) during routine training in order to monitor the execution and development of difficult elements is intriguing. However, the validity and reliability of such measurements remain unclear. Therefore, in this study, the hpeak and L of 38 vaults, performed by top-level gymnasts, were assessed by 2D and 3D analysis in order to evaluate criterion validity and both intrarater and interrater reliability of the 2D method. Validity calculations showed higher accuracy for hpeak (±95% LoA: ±3.6% of average peak height) than for L (±95% LoA: ±7.6% of average length). Minor random errors, but no systematic errors, were observed in the examination of intrarater reliability (hpeak: CV% = 0.44%, p = 0.81; L: CV% = 0.87%, p = 0.14) and interrater reliability (hpeak: CV% = 0.51%, p = 0.55; L: CV% = 0.72%, p = 0.44). In conclusion, the validity and reliability of the 2D method are deemed sufficient (particularly for hpeak, but with some limitations for L) to justify its use in routine training of the vault. Due to its simplicity and low cost, this method could be an attractive monitoring tool for gymnastics coaches

The “Journal of Functional Morphology and Kinesiology” Journal Club Series: Resistance Training

We are glad to introduce the Second Journal Club of Volume Five, Second Issue. This edition is focused on relevant studies published in the last few years in the field of resistance training, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share with you the passion for the sport, seen also from the scientific point of view

Conditioning exercises in ski jumping: biomechanical relationship of squat jumps, imitation jumps, and hill jumps

As hill jumps are very time-consuming, ski jumping athletes often perform various imitation jumps during training. The performed jumps should be similar to hill jumps, but a direct comparison of the kinetic and kinematic parameters has not been performed yet. Therefore, this study aimed to correlate 11 common parameters during hill jumps (Oberstdorf Germany), squat jumps (wearing indoor shoes), and various imitation jumps (rolling 4°, rolling flat, static; jumping equipment or indoor shoes) on a custom-built instrumented vehicle with a catch by the coach. During the performed jumps, force and video data of the take-off of 10 athletes were measured. The imitation and squat jumps were then ranked. The main difference between the hill jumps and the imitation and squat jumps is the higher maximal force loading rate during the hill jumps. Imitation jumps performed on a rolling platform, on flat ground were the most similar to hill jumps in terms of the force–time, and leg joint kinematic properties. Thus, non-hill jumps with a technical focus should be performed from a rolling platform with a flat inrun with normal indoor shoes or jumping equipment, and high normal force loading rates should be the main focus of imitation training

Simple assessment of height and length of flight in complex gymnastic skills: validity and reliability of a two-dimensional video analysis method

In artistic gymnastics, the possibility of using 2D video analysis to measure the peak height (hpeak) and length of flight (L) during routine training in order to monitor the execution and development of difficult elements is intriguing. However, the validity and reliability of such measurements remain unclear. Therefore, in this study, the hpeak and L of 38 vaults, performed by top-level gymnasts, were assessed by 2D and 3D analysis in order to evaluate criterion validity and both intrarater and interrater reliability of the 2D method. Validity calculations showed higher accuracy for hpeak (±95% LoA: ±3.6% of average peak height) than for L (±95% LoA: ±7.6% of average length). Minor random errors, but no systematic errors, were observed in the examination of intrarater reliability (hpeak: CV% = 0.44%, p = 0.81; L: CV% = 0.87%, p = 0.14) and interrater reliability (hpeak: CV% = 0.51%, p = 0.55; L: CV% = 0.72%, p = 0.44). In conclusion, the validity and reliability of the 2D method are deemed sufficient (particularly for hpeak, but with some limitations for L) to justify its use in routine training of the vault. Due to its simplicity and low cost, this method could be an attractive monitoring tool for gymnastics coaches

Effects of beta-alanine supplementation and interval training on physiological determinants of severe exercise performance

Introduction: We aimed to manipulate physiological determinants of severe exercise performance. We hypothesized that (1) beta-alanine supplementation would increase intramuscular carnosine and buffering capacity and dampen acidosis during severe cycling, (2) that high-intensity interval training (HIT) would enhance aerobic energy contribution during severe cycling, and (3) that HIT preceded by beta-alanine supplementation would have greater benefits. Methods: Sixteen active men performed incremental cycling tests and 90-s severe (110% peak power) cycling tests at three time points: before and after oral supplementation with either beta-alanine or placebo, and after an 11-days HIT block (9 sessions, 4×4min), which followed supplementation. Carnosine was assessed via MR spectroscopy. Energy contribution during 90-s severe cycling was estimated from the O2 deficit. Biopsies from m. vastus lateralis were taken before and after the test. Results: Beta-alanine increased leg muscle carnosine (32±13%, d=3.1). Buffering capacity and incremental cycling were unaffected, but during 90-s severe cycling, beta-alanine increased aerobic energy contribution (1.4±1.3%, d=0.5), concurrent with reduced O2 deficit (−5.0±5.0%, d=0.6) and muscle lactate accumulation (−23±30%, d=0.9), while having no effect on pH. Beta-alanine also enhanced motivation and perceived state during the HIT block. There were no between-group differences in adaptations to the training block, namely increased buffering capacity (+7.9±11.9%, p=0.04, d=0.6, n=14) and glycogen storage (+30±47%, p=0.04, d=0.5, n=16). Conclusions: Beta-alanine did not affect buffering considerably, but has beneficial effects on severe exercise metabolism as well as psychological parameters during intense training phases

Associations between cytokines, endocrine stress response, and gastrointestinal symptoms in autism spectrum disorder

PosterAutism spectrum disorder (ASD) is characterized by impairments in social communication and abnormal repetitive behavior patterns. Recent studies have shown a strong association between ASD and gastrointestinal (GI) symptomatology. Some individuals with ASD show altered reactivity to stress, as well as altered immune markers, particularly stress responsive cytokines including TNF-alpha and IL-6. To assess potential relationships between GI symptoms and stress response, we examined whether GI symptoms are associated with increases in stress-associated endocrine markers and cytokines in ASD. We also conducted exploratory analyses the examine the relationship between IL-6, TNF-alpha, cortisol, and intelligence, as well as the effects of the presence or absence of co-occurring medical conditions on the relationship between IL-6, TNF-alpha, cortisol, and GI symptoms. Given the aforementioned findings, we expected to find positive relationships between GI symptoms and biomarkers of stress, including cortisol levels, IL-6, and TNF-alpha