Does Anaerobic Speed Reserve Influence Post-Activation Performance Enhancement in Endurance Runners?

We investigated the influence of anaerobic speed reserve (ASR) on post-activation performance enhancement (PAPE). Twenty-two endurance runners and triathletes were evaluated for maximum sprinting speed (MSS) and countermovement jump (CMJ) before (non-fatigued) and after (fatigued) an incremental running test. They were allocated in LASR (low-ASR) and HASR (high-ASR) groups for comparisons between conditions. HASR showed greater CMJ and MSS (both p<0.005) performances, with enhanced CMJ in fatigued condition (p=0.008). Significant correlations were found between ASR, CMJ and MSS in both conditions (p≤0.01) for the entire sample, and between ∆CMJ and ∆MSS (p=0.001) in LASR. Our results show that ASR profile influences PAPE.

Squat and countermovement jump performance across a range of loads: a comparison between Smith machine and free weight execution modes in elite sprinters.

The aims of this study were to: 1) provide and compare the height achieved during Smith machine (SM) and free weight (FW) loaded jumps executed over a wide spectrum of loads (40-120% of body mass [BM]); and 2) test the difference between loaded and unloaded squat jump (SJ) and countermovement jump (CMJ) attempts in ten highly trained male sprinters. On the first visit, athletes performed unloaded SJ and CMJ, loaded SJ with loads corresponding to 40, 60, 80, 100, and 120% BM, and loaded CMJ at 100% BM using an Olympic barbell (FW). On the second visit, they performed loaded SJ and CMJ tests under the same loading conditions on the SM device and, subsequently, a half-squat one-repetition maximum (1RM) assessment. The relative strength (RS = 1RM/BM) of the athletes was 2.54 ± 0.15. Loaded SJ performance was similar between SM and FW, and across all loading conditions. Differences in favour of CMJ (higher jump heights compared with SJ) were superior in the unloaded condition but decreased progressively as a function of loading. In summary, sprinters achieved similar SJ heights across a comprehensive range of loads, regardless of the execution mode (FW or SM). The positive effect of the countermovement on jump performance is progressively reduced with increasing load.

Correlations between jump measures and competitive performance remain stable over time in top-level sprinters.

BACKGROUND: We examined the relationships between jump performance measures, sprint tests, and 100-m competition times in 11 top-level sprinters during two successive competitive 4-week mesocycles. METHODS: Physical tests were performed 7-12 days before 3 sequential competitions. Sprinters completed standing long jump, squat and countermovement jumps, and 60-m sprint tests on each occasion. A repeated measures analysis of variance was used to compare the physical assessments and actual competition results among the three moments. A Pearson product-moment correlation coefficient was used to analyze the relationships between the multiple variables over the consecutive mesocycles. Significance level was set at P<0.05. RESULTS: No significant differences were observed among the periods for any jump or sprint performance measure (ES ranging from 0.02 to 0.33; P>0.05). Very large to nearly perfect correlations were observed for all sprint and jump variables and 100-m dash times in the three moments analyzed (P<0.05). CONCLUSIONS: Our data indicate that simple jump measures can be prospectively used to monitor sprint performance. Notably, the standing long jump test was the most consistently related to 100-m time. This simple strategy may help track and field coaches to better adjust the competitive approach of their sprinters, thus optimizing their peak performance.

Predicting Recreational Runners' Marathon Performance Time During Their Training Preparation.

ABSTRACT: Esteve-Lanao, J, Del Rosso, S, Larumbe-Zabala, E, Cardona, C, Alcocer-Gamboa, A, and Boullosa, DA. Predicting marathon performance time throughout the training preparation in recreational runners. J Strength Cond Res 35(11): 3218-3224, 2021-The objective of this study was to predict marathon performance at different time points along the season using different speeds derived from ventilatory thresholds and running economy (RE). Sixteen recreational runners (8 women and 8 men) completed a 16-week marathon training macrocycle. Aerobic threshold (AeT), anaerobic threshold (AnT), and maximal oxygen uptake were assessed at the beginning of the season, whereas speeds eliciting training zones at AeT and AnT, and RE were evaluated at 5-time points during the season (M1-M5). Analyses of variance and hierarchical regression analyses were conducted. Training improved AeT and AnT speeds at M2 vs. M1 (p = 0.001) and remained significantly higher at M3, M4, and M5 (p = 0.001). There was a significant effect of time (p = 0.003) for RE, being higher at M4 and M5 compared with M1 and M3. Significant correlations were found between marathon performance and speeds at AeT and AnT at every time point (r = 0.81-0.94; p < 0.05). Speed at AnT represented the main influence (65.9 and 71.41%) in the final time prediction at M1 and M2, whereas speed at AeT took its place toward the end of the macrocycle (76.0, 80.4, and 85.0% for M3, M4, and M5, respectively). In conclusion, assessment of speeds at AeT and AnT permits for reasonable performance prediction during the training preparation, therefore avoiding maximal testing while monitoring 2 fundamental training speeds. Future research should verify if these findings are applicable to runners of different levels and other periodization models.

Cycling Performance Enhancement After Drop Jumps May Be Attributed to Postactivation Potentiation and Increased Anaerobic Capacity.

de Poli, RAB, Boullosa, DA, Malta, ES, Behm, D, Lopes, VHF, Barbieri, FA, and Zagatto, AM. Cycling performance enhancement after drop jumps may be attributed to postactivation potentiation and increased anaerobic capacity. J Strength Cond Res 34(9): 2465-2475, 2020-The study aimed to investigate the effects of drop jumps (DJs) on supramaximal cycling performance, anaerobic capacity (AC), electromyography, and fatigue. Thirty-eight recreational cyclists participated into 3 independent studies. In study 1 (n = 14), neuromuscular fatigue was assessed with the twitch interpolation technique. In study 2 (n = 16), the AC and metabolic contributions were measured with the maximal accumulated oxygen deficit method and the sum of the glycolytic and phosphagen pathways. In study 3 (n = 8), postactivation potentiation (PAP) induced by repeated DJs was evaluated. The DJ protocol was effective for significantly improving cycling performance by +9.8 and +7.4% in studies 1 and 2, respectively (p ≤ 0.05). No differences were observed in electromyography between conditions (p = 0.70); however, the force evoked by a doublet at low (10 Hz) and high frequencies (100 Hz) declined for control (-16.4 and -23.9%) and DJ protocols (-18.6 and -26.9%) (p < 0.01). Force decline was greater in the DJ condition (p < 0.03). Anaerobic capacity and glycolytic pathway contributions were +7.7 and +9.1% higher after DJ protocol (p = 0.01). Peak force during maximal voluntary contraction (+5.6%) and doublet evoked force at 100 Hz (+5.0%) were higher after DJs. The DJ protocol induced PAP, improved supramaximal cycling performance, and increased AC despite higher peripheral fatigue.

Beating Yourself: How Do Runners Improve Their Own Records?

BACKGROUND: Pacing studies suggest the distribution of effort for optimizing performance. Cross-sectional studies of 1-mile world records (WRs) suggest that WR progression includes a smaller coefficient of variation of velocity. PURPOSE: This study evaluates whether intraindividual pacing used by elite runners to break their own WR (1 mile, 5 km, and 10 km) is related to the evolution of pacing strategy. We provide supportive data from analysis in subelite runners. METHODS: Men's WR performances (with 400-m or 1-km splits) in 1 mile, 5 km, and 10 km were retrieved from the IAAF database (from 1924 to present). Data were analyzed relative to pacing pattern when a runner improved their own WR. Similar analyses are presented for 10-km performance in subelite runners before and after intensified training. RESULTS: WR performance was improved in 1 mile (mean [SD]: 3:59.4 [11.2] to 3:57.2 [8.6]), 5 km (13:27 [0:33] to 13:21 [0:33]), and 10 km (28:35 [1:27] to 28:21 [1:21]). The average coefficient of variation did not change in the 1 mile (3.4% [1.8%] to 3.6% [1.6%]), 5 km (2.4% [0.9%] to 2.2% [0.8%]), or 10 km (1.4% [0.1%] to 1.5% [0.6%]) with improved WR. When velocity was normalized to the percentage mean velocity for each race, the pacing pattern was almost identical. Very similar patterns were observed in subelite runners in the 10 km. When time improved from 49:20 (5:30) to 45:56 (4:58), normalized velocity was similar, terminal RPE increased (8.4 [1.6] to 9.1 [0.8]), coefficient of variation was unchanged (4.4% [1.1%] to 4.8% [2.1%]), and VO2max increased (49.8 [7.4] to 55.3 [8.8] mL·min-1·kg-1). CONCLUSION: The results suggest that when runners break their own best performances, they employ the same pacing pattern, which is different from when WRs are improved in cross-sectional data.

Combined effects of very short "all out" efforts during sprint and resistance training on physical and physiological adaptations after 2 weeks of training.

PURPOSE: The aim of this study was to compare the combined effects of resistance and sprint training, with very short efforts (5 s), on aerobic and anaerobic performances, and cardiometabolic health-related parameters in young healthy adults. METHODS: Thirty young physically active individuals were randomly allocated into four groups: resistance training (RTG), sprint interval training (SITG), concurrent training (CTG), and control (CONG). Participants trained 3 days/week for 2 weeks in the high-intensity interventions that consisted of 6-12 "all out" efforts of 5 s separated by 24 s of recovery, totalizing ~ 13 min per session, with 48-72 h of recovery between sessions. Body composition, vertical jump, lower body strength, aerobic and anaerobic performances, heart rate variability (HRV), and redox status were evaluated before and after training. Total work (TW), rating of perceived exertion (CR-10 RPE) and mean HR (HRmean) were monitored during sessions. Incidental physical activity (PA), dietary intake and perceived stress were also controlled. RESULTS: Maximum oxygen consumption (VO2max) significantly increased in SITG and CTG (P < 0.05). Lower body strength improved in RTG and CTG (P < 0.05), while countermovement jump (CMJ) was improved in RTG (P = 0.04) only. Redox status improved after all interventions (P < 0.05). No differences were found in TW, PA, dietary intake, and psychological stress between groups (P > 0.05). CONCLUSIONS: RT and SIT protocols with very short "all out" efforts, either performed in isolation, or combined, demonstrated improvement in several physical fitness- and health-related parameters. However, CT was the most efficient exercise intervention with improvement observed in the majority of the parameters.

The validity and reliability of the "My Jump App" for measuring jump height of the elderly.

BACKGROUND: The ability to jump has been related to muscle strength and power, speed and amplitude of the lower limbs movements, and specifically for the elderly, the vertical jump has been shown to be a good predictor of functional capacity and risk of falling. The use of a mobile application (App) which can measure the vertical jump (i.e., iPhone App My Jump) has recently emerged as a simple, cheap and very practical tool for evaluation of jump ability. However, the validity of this tool for the elderly population has not been tested yet. The elderly usually perform very low jumps and therefore the signal-to-noise ratio may compromise the validity and reliability of this method. Thus, the aim of the current study was to verify the validity and reliability of the iPhone App "My Jump" for the evaluation of countermovement jump (CMJ) height within an elderly population. METHODS: After familiarization, 41 participants performed three CMJs assessed via a contact mat and the My Jump App. The intraclass correlation coefficient (ICC) was used to verify the relative reliability, while the coefficient of variation (CV%) and the typical error of measurement (TEM) were used to verify the absolute reliability. Pearson's correlation coefficient was used to verify the strength of the relationship between methods (i.e., concurrent validity), a Bland-Altman plot to show their agreement, and the Student's t-test to identify systematic bias between them. For reliability analyses, all jumps were considered (i.e., 123). All jumps (i.e., 123), the average height of each attempt (i.e., 41), and the highest jump, were considered for validity analyses. RESULTS: The CMJ height of the highest jump was 10.78 ± 5.23 cm with contact mat, and 10.87 ± 5.32 with My Jump App, with an identified systematic bias of 0.096 cm (P = 0.007). There was a nearly perfect correlation between methods (r = 0.999; P = 0.000, in all cases) with a very good agreement observed (0.3255 to -0.5177 cm, 0.2797 to -0.5594 cm, and 0.3466 to -0.6264 cm, for highest jump height, average jump height, and all jump heights, respectively). The ICC of the My Jump App was 0.948, the TEM was 1.150 cm, and the CV was 10.10%. CONCLUSION: Our results suggest that the My Jump App is a valid and reliable tool compared to the contact mat for evaluating vertical jump performance in the elderly. Therefore, it allows a simple and practical assessment of lower limbs' power in this population. For the elderly, as well as for other populations with low jumping heights, the highest jump height and the average jump height could be used indistinctly.

Improvements in Attention and Cardiac Autonomic Modulation After a 2-Weeks Sprint Interval Training Program: A Fidelity Approach.

This study aimed to: (1) investigate the influence of a 2-weeks sprint interval training (SIT) program on aerobic capacity, cardiac autonomic control, and components of attention in young healthy university students; and (2) to ascertain whether training fidelity would influence these adaptations. One hundred and nine participants were divided into an experimental (EG) and control (CG) groups. The EG performed a SIT program that consisted of 6 sessions of 4 × 30 s "all-out" efforts on a cycle ergometer, interspersed with active rests of 4 min. The criterion for fidelity was achieving >90% of estimated maximum heart rate (HR) during sprint bouts. After analyses, the EG was divided into HIGH (n = 26) and LOW (n = 46) fidelity groups. Components of attention were assessed using the Attention Network Test (ANT). Aerobic capacity (VO2max) was estimated while the sum of skinfolds was determined. Autonomic control of HR was assessed by means of HR variability (HRV) and HR complexity at rest and during ANT. Both HIGH and LOW significantly increased aerobic capacity, vagal modulation before and during ANT, and executive control, and decreased body fatness after SIT (p < 0.05). However, only participants from HIGH showed an increase in HR complexity and accuracy in ANT when compared to LOW (p < 0.05). Two weeks of SIT improved executive control, body fatness, aerobic fitness, and autonomic control in university students with better results reported in those individuals who exhibited high fidelity.

Acute and Chronic Effects of Endurance Running on Inflammatory Markers: A Systematic Review.

In order to understand the effect of endurance running on inflammation, it is necessary to quantify the extent to which acute and chronic running affects inflammatory mediators. The aim of this study was to summarize the literature on the effects of endurance running on inflammation mediators. Electronic searches were conducted on PubMED and Science Direct with no limits of date and language of publication. Randomized controlled trials (RCTs) and non-randomized controlled trials (NRCTs) investigating the acute and chronic effects of running on inflammation markers in runners were reviewed by two researchers for eligibility. The modified Downs and Black checklist for the assesssments of the methodological quality of studies was subsequently used. Fifty-one studies were finally included. There were no studies with elite athletes. Only two studies were chronic interventions. Results revealed that acute and chronic endurance running may affect anti- and pro-inflammatory markers but methodological differences between studies do not allow comparisons or generalization of the results. The information provided in this systematic review would help practitioners for better designing further studies while providing reference values for a better understanding of inflammatory responses after different running events. Further longitudinal studies are needed to identify the influence of training load parameters on inflammatory markers in runners of different levels and training background.

Heart rate recovery after aerobic and anaerobic tests: is there an influence of anaerobic speed reserve?

The present study assessed if differences in the metabolic profile, inferred from the anaerobic speed reserve (ASR), would influence the dynamics of heart rate recovery (HRR) after two modes of exercise. Thirty-nine physical education students (14 females and 25 males) volunteered for this study. Participants carried out three separate testing sessions to assess maximal sprinting speed (MSS, 1st session), repeated sprint ability (RSA, 2nd session) and maximal aerobic speed (MAS) using the Université of Montreal Track Test (UMTT, 3rd session). ASR was defined as the difference between MSS and MAS. Heart rate was continuously registered throughout the tests and during the 5-min post-test recovery. To evaluate the influence of ASR on post-exercise, HRR comparisons between ASR-based groups [high ASR vs. low ASR] and sex groups (males vs. females) were performed. Significant differences (P < 0.05) were found between high ASR and low ASR groups of the same sex for indices of relative HRR after the RSA and UMTT. In addition, after the RSA test, males from the high ASR group had a significantly slower HRR kinetics compared with the males of the low ASR (P < 0.05) and the females of high ASR (P < 0.05); whereas females of the high ASR groups had a faster HRR kinetics compared with the females of low ASR group (P < 0.05). Our results showed that in males, post-exercise HRR could be related to the ASR, whereas in females, the influence of ASR is less clear.

Does Concurrent Training Intensity Distribution Matter?

Varela-Sanz, A, Tuimil, JL, Abreu, L, and Boullosa, DA. Does concurrent training intensity distribution matter? J Strength Cond Res 31(1): 181-195, 2017-Previous research has demonstrated the influence of intensity distribution on endurance training adaptations. However, no study has addressed the influence of intensity distribution on the effectiveness of concurrent training (CT). The main objective of this study was to compare the effects of 2 CT programs with different training intensity distribution and externally equated loads on physical fitness. Thirty-one sport science students volunteered and were evaluated for resting heart rate variability (HRV), countermovement jump, bench press, half squat, and maximum aerobic speed (MAS). All were randomly distributed into either a traditional-based training group (TT; n = 11; 65-75% of MAS, combined with 10-12 repetition maximum [RM]), polarized training group (PT; n = 10; 35-40% and 120% of MAS, combined with 5RM and 15RM), or control group (CG; n = 10). After 8 weeks of training (3 daysweek), TT and PT exhibited similar improvements in MAS, bench press, and half squat performances. No differences were observed between TT and PT groups for perceived loads. There were no changes in HRV for any group, although TT exhibited a reduction in resting heart rate. Compared with other groups, the PT group maintained jump capacity with an increment in body mass and body mass index without changes in body fatness. In conclusion, PT induced similar improvements in physical fitness of physically active individuals when compared with TT. However, PT produced a lower interference for jumping capacity despite an increment in body mass, whereas TT induced greater bradycardia. Extended studies with different intensity distributions should be conducted to better determine the dose-response of CT in various populations.

Can Pacing Be Regulated by Post-Activation Potentiation? Insights from a Self-Paced 30 km Trial in Half-Marathon Runners.

PURPOSE: Given the co-existence of post-activation potentiation (PAP) and fatigue within muscle, it is not known whether PAP could influence performance and pacing during distance running by moderating fatigue. The aim of this study was to assess the influence of PAP on pacing, jumping and other physiological measures during a self-paced 30 km trial. METHODS: Eleven male endurance-trained runners (half-marathon runners) volunteered to participate in this study. Runners participated in a multi-stage 30 km trial. Before the trial started, determination of baseline blood lactate (bLa) and countermovement jump (CMJ) height was performed. The self-paced 30 km trial consisted of 6 × 5 km splits. At the end of each 5 km split (60 s break), data on time to complete the split, CMJ height, Rating of Perceived Exertion (RPE) and blood lactate were collected while heart rate was continuously monitored. RESULTS: There was a significant decrease in speed (e.g. positive pacing strategy after the 4th split, p<0.05) with a progressive increase in RPE throughout the trial. Compared with baseline, CMJ height was significantly (p<0.05) greater than baseline and was maintained until the end of the trial with an increase after the 5th split, concomitant with a significant reduction in speed and an increase in RPE. Significant correlations were found between ΔCMJ and ΔSPEED (r = 0.77 to 0.87, p<0.05) at different time points as well as between RPE and speed (r = -0.61 to -0.82, p<0.05). CONCLUSION: Our results indicates that fatigue and potentiation co-exist during long lasting endurance events, and that the observed increase in jump performance towards the end of the trial could be reflecting a greater potentiation potentially perhaps counteracting the effects of fatigue and preventing further reductions in speed.

Stress Markers During a Rally Car Competition.

The aim of the study was to assess the stress responses in drivers during an official rally car race and the influence of fitness and body composition on stress hormones. Fitness and body composition were assessed in 9 rally car drivers with an incremental exercise test for determination of maximum aerobic speed (MAS) and 6-site skinfold method, respectively. Before (pre) and after (post) the first stage of an official rally car race, data were collected for heart rate (HR), blood samples were collected for analysis of hormones (i.e., epinephrine [EPI], norepinephrine [NE], cortisol, and aldosterone) and metabolites (i.e., lactate [LA], glucose, and ammonia). There were significant (p ≤ 0.05) increases in all assessed variables except glucose at postrace. Heart rate increased 93% (p ≤ 0.05) at the end of the race stage, reaching 88.77 ± 4.96% of HRpeak. Also, EPI and NE significantly (p = 0.001) increased by 45 and 65%, respectively, and LA increased by 395% (p < 0.001). Significant correlations between percent body fat (%BF) and postrace EPI (r = 0.95; p < 0.001), and percentage change of EPI (r = 0.83; p = 0.012) were observed. The MAS was not associated to any metabolic or hormonal variable. These results suggest that psycho-physiological stress induced by the race elicited important changes in hormonal and metabolic variables and that %BF could be an important mediator of psycho-physiological stress in rally car drivers. Specific programs, including both strength and aerobic training, and nutritional plans should be implemented for appropriate conditioning of rally car drivers.

Heart Rate and Cardiovascular Responses to Commercial Flights: Relationships with Physical Fitness.

The aim of this study was to examine the influence of physical fitness on cardiac autonomic control in passengers prior to, during and following commercial flights. Twenty-two, physically active men (36.4 ± 6.4 years) undertook assessments of physical fitness followed by recordings of 24-h heart rate (HR), heart rate variability (HRV), and blood pressure (BP) on a Control (no flight) and Experimental (flight) day. Recordings were analyzed using a two-way analysis of variance for repeated measures with relationships between variables examined via Pearson product-moment correlation coefficients. Compared to the Control day, 24-h HR was significantly greater (>7%) and HRV measures (5-39%) significantly lower on the Experimental day. During the 1-h flight, HR (24%), and BP (6%) were increased while measures of HRV (26-45%) were reduced. Absolute values of HRV during the Experimental day and relative changes in HRV measures (Control-Experimental) were significantly correlated with measures of aerobic fitness (r = 0.43 to 0.51; -0.53 to -0.52) and body composition (r = -0.63 to -0.43; 0.48-0.61). The current results demonstrated that short-term commercial flying significantly altered cardiovascular function including the reduction of parasympathetic modulations. Further, greater physical fitness and lower body fat composition were associated with greater cardiac autonomic control for passengers during flights. Enhanced physical fitness and leaner body composition may enable passengers to cope better with the cardiovascular stress and high allostatic load associated with air travel for enhanced passenger well-being.

Atheroprotective Properties of Serum IGF-1 in the Carotid and Coronary Territories and Beneficial Role on the Physical Fitness of the Oldest Old.

Our aim was to investigate whether physiological levels of soluble insulin-like growth factor-1 (IGF-1) associate with coronary and carotid atherosclerotic burden and physical fitness in the oldest old by means of a cross-sectional study including 100 community-dwelling individuals with no previous cardiovascular events. Linear correlation was found between IGF-1 and intima-media thickness, number of carotid plaques, and walking speed. Individuals in the upper IGF-1 tertile had smaller right and left intima-media thickness compared with the intermediate and lower tertiles, along with reduced atherosclerotic plaques. Also, walking speed was greater in the upper IGF-1 tertile. On the other hand, a nonlinear correlation was observed between IGF-1 and coronary calcification scores, with the intermediate IGF-1 tertile associated to the lowest scores of calcification and participants with lower circulating levels of IGF-1 showing higher frequency of high-risk morphology plaques. All in all, our report supports a territory-dependent, atherorefractory phenotype in the oldest old carrying middle and/or higher serum levels of IGF-1.

Physical Fitness and Dehydration Influences on the Cardiac Autonomic Control of Fighter Pilots.

BACKGROUND: Physical fitness and dehydration are factors that may influence cardiac autonomic control. We aimed to verify the influence of these factors on cardiac autonomic control before, during, and after a flight. METHODS: At the same time of day, 11 healthy fighter pilots recorded several 1-h bouts of heart rate (HR) activity during a non- (control) and a training flight day. Autonomic control of HR was examined via time domain and non-linear heart rate variability (HRV) analyses. The level of dehydration during the flight was evaluated by changes in hematocrit, while aerobic capacity, muscular strength, and body fatness were the physical fitness components evaluated. RESULTS: The flight induced a significant reduction in most parameters of HRV during flight time when compared to the control day. However, no differences were found between the days before the flight, while the root mean square of successive differences (RMSSD) of HR was the only parameter significantly reduced (11.05 ± 7.7%) after the flight. Significant correlations were observed between the sample entropy of HR during flight and aerobic capacity (r = 0.777) and body fatness (r = -0.617). Correlations between dehydration and changes in HRV (RMSSD and SD1) were also identified (r = -0.61 to -0.81). CONCLUSION: The current results demonstrated significant relationships between aerobic capacity, body fatness, and hydration status on autonomic control of HR during and after flights. No relationship to muscular strength was observed. Future studies may further elucidate the impact of these factors on pilot training in order to accommodate flight's stressors and enhance performance.