ECSS Paris 2023: OP-AP02
INTRODUCTION: High-intensity interval training (HIT) is considered effective for improving endurance performance in endurance athletes. Moreover, block periodization of HIT is well-known to provide additional performance improvements in endurance athletes (1). The effectiveness of moderate-intensity interval training (MIT) and the ideal training volume in this intensity zone have been widely discussed (2, 3). Cyclists often utilize both MIT and HIT in their annual training, yet the relative effectiveness of these two training regimes remains poorly explored. Hence, we aimed to compare the within-subject responses to a one-week MIT block characterized by longer work durations but lower effort, against a standard one-week HIT block with shorter work durations but higher effort, in cyclists. METHODS: Twenty-two cyclists (♂, 21; ♀, 1; age, 19.2(3.6)years; maximal oxygen consumption (VO2max), 69.5(6.0)mL/min/kg) first conducted a 7-day MIT block and thereafter a 6-day HIT block. Both blocks were followed by a six-day taper, and the blocks were separated by ⁓2 months of usual training. The MIT block included six MIT sessions with 5-7x10-14-min work intervals aiming for 14-15 on the Borg 6-20 rating of perceived exhaustion (RPE). The HIT block included five HIT sessions all performed as 5x8.75-min series with multiple short intervals targeting 16-18RPE. The cyclists´ maximal 1-min power output (PO) during a VO2max-test (pVO2max), PO corresponding to 4 mmol/L [blood lactate] (PO@4mmol), 15-min maximal PO (PO@15min), and VO2max were assessed before and after each training block. Potential differences in pre-test values between blocks were accounted for in the statistical analysis. RESULTS: The total work interval duration in MIT and HIT block were 7:04 and 3:42 hours, respectively, with average RPE during work intervals being 14.5(0.3) and 17.1(0.4), which corresponded to 65.8(4.2) and 70.9(5.8)% of pVO2max, 85.5(3.6) and 90.0(2.7)% of HRmax, and 2.9(0.8) and 7.5(1.5)mmol/L [blood lactate], respectively. Both the MIT and HIT block effectively improved the cyclists´ pVO2max (2.4(4.5) and 3.7(3.2)%), PO@4mmol (4.5(4.5) and 2.1(2.7)%), PO@15min (4.9(8.7) and 2.8(5.3)%), and VO2max (1.5(3.9) and 2.4(3.8)%). The improvement gains did not differ between blocks, except for the improvement in PO@4mmol which was greater following the MIT block compared to the HIT block (p=0.05). CONCLUSION: Both a MIT block, featuring lower exercise intensity but longer accumulated work interval durations, and a HIT-block, characterized by higher exercise intensity but shorter accumulated work interval durations, effectively enhance endurance performance determinants and PO@15min. Notably, the significantly greater PO@4mmol improvement following the MIT block compared to the HIT block indicates some work intensity-specific training adaptations. REFERENCES: 1 Clark et al. PLoS One. 2014;9(12):1–14 2 Burnley et al. Med Sci Sports Exerc. 2022 Jun 1;54(6):1032-1034 3 Foster et al. Med Sci Sports Exerc. 2022 Jun 1;54(6):1028-1031
Read CV Ingvill OddenECSS Paris 2023: OP-AP02
INTRODUCTION: Sleep is critical for physiological and psychological restoration and is widely recognized as one of the important factors for athletic recovery. There are indications that sleep may be affected by the fluctuating ovarian hormones across the natural menstrual cycle (MC). However, there is a lack of consensus in the literature due to differences in the determination and verification of MC phase, along with a focus on clinical populations rather than athletic women. Accordingly, the aim of this study was to investigate the effects of MC phase on sleep stages and markers of objective and perceived sleep quality in eumenorrheic, endurance trained women. METHODS: Sixteen naturally menstruating, endurance-trained women (mean±standard deviation: 31±5 years; 62±7 kg, VO2max 55±5 mL٠kg-1٠min-1) were included. For two MCs participants used an at-home unobtrusive sleep monitor (Somnofy) and self-reported perceived sleep quality on a visual analog scale. MC phases were determined using calendar-based counting, urinary ovulation prediction testing, and serum hormone analysis of estrogen and progesterone. Only eumenorrheic cycles (i.e., cycle length ≥21 and ≤35 days, positive urinary ovulation test and mid-luteal progesterone ≥16 nmol٠L-1) were included in the analysis. MC phases were defined as: early follicular- (EFP, first two nights after the start of menstruation), late follicular- (LFP, the two nights prior to a positive ovulation test), ovulatory- (OP, the night of a positive ovulation test and one night thereafter), mid-luteal- (MLP, the nights 7-8 days after a positive ovulation test), and late luteal-phase (LLP, the two nights prior to the onset of the subsequent menstruation). Data were analysed using linear mixed effect models in RStudio. RESULTS: MC phase had a significant main effect on the distribution of light (p=0.011), slow wave (p=0.026), and rapid eye movement (REM, p=0.008) sleep. Total sleep time was (mean±SD) 7.2±0.7h in EFP and remained stable across the MC (p=0.162). Sleep stages were distributed as follows; 56±4% light, 17±4% slow wave and 27±4% REM sleep in EFP. During MLP, there was more light (+4%, p=0.008) and less slow wave (-3%, p=0.027) sleep compared to EFP. MC phase did not have a main effect on perceived sleep quality (p=0.768), sleep efficiency (p=0.115) or wake after sleep onset (p=0.214). CONCLUSION: Endurance-trained women have more light and less deep sleep in MLP compared to EFP, despite no change in total sleep time or markers of objective or perceived sleep quality. While it is currently unclear how small changes in the distribution of sleep stages may influence an individual’s recovery and wellbeing, these findings indicate that MC phase, among other factors (e.g. stress, training load, etc.), should be considered when monitoring or managing sleep in female endurance women.
Read CV Madison TaylorECSS Paris 2023: OP-AP02
INTRODUCTION: Running economy plays a critical role in endurance running performance and can be enhanced by adding strength training to daily running [1]. However, the effects of strength training on endurance running performance vary among individuals [2] because the importance of muscle functions for each runner differs depending on running forms. For example, rearfoot strikers demonstrate greater activation of biceps femoris than forefoot strikers [3]. In addition, runners with a large knee range of motion (ROM) activate rectus femoris during the propulsion while runners with a small knee ROM tend to utilize energy through the stretch-shortening cycle (SSC) [4]. This study aimed to classify runners based on running forms and examine the relationships between muscle functions and endurance running performance within classified groups. METHODS: 120 endurance runners (60 males) participated in this study. The participants were tested for muscle functions, including isometric and isokinetic (30°/s and 180°/s) knee extension/flexion torque, slow SSC ability (CMJ height), and fast SSC ability (drop jump and 3-rebound jump performances). Endurance running performance was assessed from the oxygen cost of running at 11 km/h and seasonal records. Ankle joint angle at touch-down and knee joint ROM during the stance phase were measured during running at 11 km/h. Cluster analysis was conducted based on two kinematic variables in each sex. Pearson correlation analysis was performed in each cluster to assess the relationships between muscle functions and endurance running performance. RESULTS: The runners were divided into four clusters for each sex. In both sexes, there was a positive relationship between knee flexion torque and endurance running performance in runners who exhibited ankle dorsiflexion at touch-down (r=0.54–0.59). A positive relationship was found between isometric knee extension torque and endurance running performance in female runners who exhibited ankle plantarflexion at touch-down (r=0.60–0.83). Isometric and slow isokinetic knee extension torque was positively correlated to running economy in male runners with a large knee ROM (r=0.52–0.61), while fast isokinetic knee flexion torque and fast SSC ability relative to slow SSC ability were positively associated with endurance running performance in those with a small knee ROM (r=0.42–0.85). CONCLUSION: The relationships between muscle functions and endurance running performance varied depending on the individual’s running forms, as suggested by previous research findings [3, 4]. In addition, knee flexion strength appeared to be more critical in males, whereas the importance of knee extension strength may be greater in females for better endurance running performance. Thus, when runners and coaches select strength training, running forms as well as sex should be considered to maximize the improvement in endurance running performance. [1] Eihara et al. (2022) [2] Patoz et al. (2022) [3] Yong et al. (2014) [4] Lussiana et al. (2017)
Read CV Yuuri EiharaECSS Paris 2023: OP-AP02