Discipline-specific Torque-Velocity Profiles and Musculotendinous Morphology in Athletes.

OBJECTIVES: The aim of this study was to compare torque-velocity profiles, muscle architecture, tendon dimensions, and bilateral-symmetry between competitive cyclists (CY), competitive runners (RN), ice-hockey players (IH), basketball players (BP), and physically-active individuals (CN) (n=10 for each group). METHODS: Vastus lateralis (VL) muscle and patellar tendon (PT) structures were determined with B-mode ultrasonography, and maximal knee extensor isokinetic torque was assessed at three different velocities. RESULTS: Optimal torque and velocity were lower in runners than CY, BP and IH (p<0.05). Maximal power was similar between the athlete groups but greater than CN (p<0.05). Furthermore, RN and BP reached their peak-torque at longer muscle lengths compared to IH and CY (p<0.05). RN had the lowest VL muscle thickness and the greatest fascicle length, while CY had the greatest pennation angle (p<0.05). CY had the greatest PT thickness, particularly at the proximal and medial sites, while BP at the distal point (p<0.05), with similar trends observed for PT cross-sectional-area. CONCLUSIONS: Our findings show that even if power generating capacity is similar between athletic disciplines, there are discipline-specific muscle adaptations, where particularly runners appear to have muscles adapted for speed rather than torque development, while in cyclists, velocity is sacrificed for torque development.

Obesity-related reduced spirometry and altered breathing pattern are associated with mechanical disadvantage of the diaphragm.

The aim of this study was to characterize the breathing patterns of individuals with obesity during routine activities such as sitting and standing, and to identify potential contributors to alterations in these patterns. Measurements performed in 20 male subjects with obesity (BMI, 31.8±1.5 kg/m2) and 20 controls (BMI, 23.5±1.4 kg/m2) included anthropometric parameters, breathing-patterns in sitting and standing positions, spirometry, maximal respiratory pressures, and diaphragm B-mode ultrasonography. Individuals with obesity exhibited lower tidal volume and increased respiratory rate to maintain a similar minute-ventilation (p<0.05). Subjects with obesity demonstrated impaired spirometry and respiratory muscle strength, with inspiratory functions being notably compromised (p<0.05). Individuals with obesity had a greater diaphragm thickness at end inspiration but lower thickening-fraction at end quiet and forced breathings and reduced diaphragmatic displacement and excursion during maximal breaths (p<0.05). BMI was negatively associated with all respiratory function markers (p<0.05). Individuals with obesity exhibit a higher respiratory rate but lower tidal volume, likely to accommodate decreased compliance and excess thoracic and abdominal fat, further hindering inspiratory function. Moreover, increased adiposity is associated with a thicker but weaker diaphragm, primarily due to the diaphragm's mechanical disadvantage rather than its intrinsic inability to generate force.

Cycling through the ranks: a cross-sectional analysis of endurance, strength and body composition indicators in junior, elite, and amateur competitive road cyclists.

BACKGROUND: The objective of the present study was to compare different performance indicators, encompassing endurance, body composition, and maximal and explosive strength markers, among competitive Lithuanian cyclists across different age and performance categories. METHODS: Thirty Lithuanian male cyclists in elite (EL, N.=10), amateur (AM, N.=10), and junior (JU, N.=10) categories underwent body composition analysis, knee extensors' isometric strength and ultrasound measurements, maximal incremental exercise tests, cycling efficiency protocol, and sprint performance evaluations. Additionally, competition results and power profiles were analyzed. RESULTS: EL cyclists had greater experience and higher annual kilometers (P<0.05). Quadriceps muscle size exhibited significant differences, being greater in EL than JU (P<0.05), whereas no noteworthy variations were observed in body fat or isometric strength. EL athletes demonstrated higher maximal oxygen consumption, maximal aerobic power, and sprint performance compared to JU and AM, particularly when considering absolute power metrics (P<0.05). Interestingly, despite JU achieving lower ranks in competitions, power profiles differed minimally between EL and JU. Furthermore, both JU and AM expended more energy during competitions (P<0.05). CONCLUSIONS: The study highlights disparities among Lithuanian cyclists, with EL cyclists showcasing advantages in endurance capacity and better competition outcomes, possibly due to their extensive experience, leading to a more efficient energy utilization. This research enhances our understanding of the multifaceted nature of the sport performance within the realm of Lithuanian cycling.

Relationships between muscle quality, subcutaneous adipose tissue, and sprint performance markers of competitive cyclists.

BACKGROUND: Many variables are considered to be determinants of cycling sprint performance. Among them, the importance of skeletal muscle properties in relation to cycling performance has been consistently underlined. The aim of the present study was to evaluate the vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM), echo intensity (EI) and subcutaneous adipose tissue (SAT) content in a group of competitive cyclists and to identify whether these are related to sprint performance. METHODS: Muscle echo intensity was evaluated by ultrasound in 16 highly trained competitive cyclists. The cyclists performed a maximal-intensity sprint session comprising four 15 s maximal sprints on a Wingate bike with 2 min of recovery between each. Pearson correlational analysis with linear regression was used to identify significant relationships between the criteria EI and SAT content and the sprint performance variables. RESULTS: Muscle EI correlated strongly with sprint performance markers (r=from 0.54 to 0.62; P<0.05), while SAT content and body fat percentage correlated trivially to moderately with sprint performance (r=from 0.07 to 0.40; P>0.05). CONCLUSIONS: Overall, muscle quality of knee extensors was positively related to sprint performance markers, but SAT content was not. Although additional studies are needed, muscle quality may represent a valid body composition indicator and may be helpful for supporting sprint performance optimization procedures in competitive cyclists.

Differences in Knee Extensors' Muscle-Tendon Unit Passive Stiffness, Architecture, and Force Production in Competitive Cyclists Versus Runners.

To describe the possible effects of chronic specific exercise training, the present study compared the anthropometric variables, muscle-tendon unit (MTU) architecture, passive stiffness, and force production capacity between a group of competitive cyclists and runners. Twenty-seven competitive male cyclists (n = 16) and runners (n = 11) participated. B-mode ultrasound evaluation of the vastus lateralis muscle and patellar tendon as well as passive stiffness of the knee extensors MTU were assessed. The athletes then performed a test of knee extensor maximal voluntary isometric contractions. Cyclists displayed greater thigh girths, vastus lateralis pennation angle and muscle thickness, patellar tendon cross-sectional area, and MTU passive stiffness than runners (P < .05). Knee extensor force production capacity also differed significantly, with cyclists showing greater values compared with runners (P < .05). Overall, the direct comparison of these 2 populations revealed specific differences in the MTU, conceivably related to the chronic requirements imposed through the training for the different disciplines.

Impact of methionine restriction on muscle aerobic metabolism and hypertrophy in young and old mice on an obesogenic diet.

Methionine restriction (MR) reduces inflammation and increases longevity. We studied the effects of MR (0.17% kCal methionine, 10% kCal fat) and MR + high-fat diet (HFD) (0.17% methionine, 45% kCal fat) and overload-induced hypertrophy on inflammation, angiogenesis and mitochondrial activity in the hind-limb muscle in 10- and 26-month-old male C57BL/6J mice. Plasma IL-6 concentrations were higher in old compared to young mice. M. plantaris hypertrophy was accompanied by increased p-Akt, without a significant change in Akt and VEGF levels. In young mice on a HFD or MR + HFD diet the SDH activity was higher than in those from mice on other diets, irrespective of overload. There were no significant differences in total NAD concentration in the m. gastrocnemius. MR enhanced the skeletal muscle hypertrophic response in old age that was accompanied with an increase in p-Akt without significant changes in muscle oxidative capacity, low-grade systemic inflammation, NAD, VEGF or Akt levels.

Performance indicators and functional adaptive windows in competitive cyclists: effect of one-year strength and conditioning training programme.

Changes and relationships between cycling performance indicators following a one-year strength and conditioning training have not been totally clarified. The aims of this study are to investigate (i) the effect of a combined one-year strength and conditioning training programme on performance indicators and the possible relationships between these indicators, and (ii) the existence of possible endurance-functional-adaptive windows (EFAWs) linked to changes in muscular strength and body composition markers. Functional and lactate threshold power (FTP and LTP), maximal strength (1RM) and body composition (body mass index [BMI], body cell mass [BCM] and phase angle [PA]) were measured at the beginning and the end of a one-year strength and conditioning training programme of thirty cyclists. Correlations, differences, and predictive analysis were performed among parameters. Significant differences were found between pre- and post-conditioning programme results for FTP, LTP, 1RM (p < 0.0001) and BCM (p = 0.038). When expressed as power output (W), FTP and LTP were significantly correlated with 1RM (r = 0.36, p = 0.005 and r = 0.37, p = 0.004, respectively), body mass (r = 0.30 and p = 0.02), BCM (r = 0.68, p < 0.001) and PA (r = 0.42 and 0.39, respectively and p < 0.001). When expressed as W·kg-¹, these power thresholds were strongly correlated with body mass (r = -0.56 and -0.61, respectively) and BMI (r = -0.57 and -0.61 respectively) with p < 0.001. Predictive polynomial regressions revealed possible endurance and strength adaptation zones. The present findings indicated beneficial impacts of one-year strength and conditioning training on cycling performance indicators, confirmed the correlation between performance indicators, and suggested the existence of different EFAWs. Strategies aiming to improve performance should consider cyclist characteristics and performance goals to achieve EFAWs and thereby enhance cycling performance.

The role of age on neuromuscular performance decay induced by a maximal intensity sprint session in a group of competitive endurance athletes.

Age-related changes in the neuromuscular system functions may affect profoundly high-level athletes' performance across their careers. The present study aimed to analyse the fatiguing effect of a maximal intensity sprint session (MISS) on competitive athletes of different ages. Thirty-one competitive endurance athletes completed a knee extensors and flexors' maximal-voluntary-isometric-contraction (MVC) test before and after a maximal-intensity-sprint-session (MISS) consisting of 4x15s Wingate-tests. The data have been stratified considering three age categories (18-28, n=11, 29-38; n=10; 39-43, n=10). Overall, both quadricep and hamstring muscles early and late rate of torque development (RTD) dropped significantly more than the maximal voluntary torque (MVT) (p<.05). Age had a significant effect on early RTD, with older athletes exhibiting greater RTD (p<.05). A significant effect of age also emerged for the changes in surface sEMG variables, in which the frequency spectrum variables dropped significantly more than the sEMG amplitude (RMS) (p<.05). The dynamics of changes in neuromuscular performance markers after a MISS suggested that getting older competitive athletes may potentially experience a greater loss in early explosive strength compared to maximal or late explosive strength.

Transition from Youth categories to Elite cycling: relationships between early career performance and UCI World Tour success.

BACKGROUND: The present study aimed to describe the possible roles of cyclists' early career performance, on the transition process to elite cycling categories. METHODS: Data from national and international databases, and results achieved during the UCI World Championships, were retrospectively analyzed considering the Italian national Youth-U16, Junior-U18, and U23 categories, and international Junior-U18 and UCI World-Tour categories. RESULTS: The 15% of Youth-U16, the 38.8% of Junior-U18 and the 60% of U23 athletes who ranked top-10 between 2007 and 2013, scored points in UCI World Tour competitions between 2012 and 2018. The 1.6% of Youth-U16, the 8.3% of Junior-U18 and 25% of U23 athletes who ranked top-10 between 2007 and 2013, ranked among the Italian Top-10 in the UCI World-Tour individual classification between 2012 and 2018. Performance level in Youth-U16 category displayed a low correlation with UCI World Tour performance while the performance level in Junior-U18 category displayed a moderate correlation. The 34% of the Junior World Championship TOP-25 cyclists, participated in the elite competition. Trivial to small correlations emerged between Junior and elite World Championship performance levels. CONCLUSIONS: Early performance seems not to represent a good predictor of elite performance, while the Junior-U18 and the U23 performance level, emerged as potential indicators of future success in the elite categories.

Occlusal Splints and Exercise Performance: A Systematic Review of Current Evidence.

The role of the dento-mandibular apparatus and, in particular, occlusion and jaw position, received increased attention during last years. In the present study, we aimed to systematically review, on the light of the new potential insights, the published literature covering the occlusal splint (OS) applications, and its impact on exercise performance. A structured search was carried out including MEDLINE®/PubMed and Scopus databases with additional integration from external sources, between March and June 2021. To meet the inclusion criteria, studies published in the English language, involving humans in vivo, published from 2000 to 2021 and that investigated the role of occlusal splints on athletes' performance were selected. Starting from the 587 identified records, 17 items were finally included for the review. Four main aspects were considered and analyzed: (1) occlusal splint characteristics and occlusion experimental conditions, (2) jump performance, (3) maximal and explosive strength, and (4) exercise technique and biomechanics. The results of the systematic literature analysis depicted a wide heterogenicity in the experimental conditions and suggested the application of the OS as a way to improve athletes' or individuals' oral health, and as a potential tool to optimize marginal aspects of exercise performance.

Effects of fasting on skeletal muscles and body fat of adult and old C57BL/6J mice.

Fasting improves metabolic health, but is also associated with loss of lean body mass. We investigated if old mice are less resistant to fasting-induce muscle wasting than adult mice. We compared changes in skeletal muscles and fat distribution in C57BL/6J mice subjected to 48-hour fasting at adult (6-month old) or old (24-month old) age. Old mice lost less weight (11.9 ± 1.5 vs 16.9 ± 2.8%, p < 0.001) and showed less (p < 0.01) pronounced muscle wasting than adult mice. Extensor digitorum longus (EDL) muscle force decreased only in adult mice after fasting. Serum IGF-1 levels were higher (p < 0.01) and showed greater (p < 0.01) decline in adult mice compared to old mice. Phosphorylation of 4EBP1 was reduced in the gastrocnemius muscles of adult mice only. Energy expenditure was slower in old mice and showed smaller fasting-induced decline than in adult mice when adjusted for variations in physical activity. There was a loss of fat mass in both age groups, but it was more pronounced in adult mice than old mice. Our results suggest that ageing-related decrease in metabolic rate protects old mice from skeletal muscle wasting during fasting.

The Impact of Fluid Loss and Carbohydrate Consumption during Exercise, on Young Cyclists' Fatigue Perception in Relation to Training Load Level.

High-level young athletes need to face a wide spectrum of stressors on their journey to élite categories. The aims of the present study are (i) to evaluate session rate of perceived exertion (sRPE) at different training impulse (TRIMP) categories and the correlations between these two variables and, (ii) evaluate the correlations between sRPE, fluid loss, and carbohydrate consumption during exercise. Data on Edward's TRIMP, sRPE, body mass loss pre- and post- exercise (∆), and carbohydrate consumption (CHO/h) during exercise have been acquired from eight male junior cyclists during a competitive season. One-way ANOVA and correlation analysis with linear regression have been performed on acquired data. sRPE resulted in a significant difference in the three TRIMP categories (p < 0.001). sRPE resulted in being very largely positively associated with TRIMP values (p < 0.001; R = 0.71). ∆ as well as CHO/h was largely negatively related with sRPE in all TRIMP categories (p < 0.001). The results confirmed the role of fluid balance and carbohydrate consumption on the perception of fatigue and fatigue accumulation dynamics independently from the training load. Young athletes' training load monitoring and nutritional-hydration support represent important aspects in athlete's exercise-induced fatigue management.

Evaluation of strategy and tactics in cycling: a systematic review of evaluation methods and possible performance implications.

INTRODUCTION: Cycling performance is affected by many factors and is the expression of a multitude of variables. Different studies aiming to describe variables determining cycling performance are focused mainly on metabolic efficiency optimization and mechanical efficiency optimization. Strategy and tactics analysis in cycling represent a key additional performance variable, however, the knowledge of methods to assess these parameters and the possible performance implications is low. The main purposes of the study were to systematically review the state of the art related to strategy and tactics analysis in cycling and describe and analyze the possible implications and possible evaluation methods of tactics and strategy in cycling. EVIDENCE ACQUISITION: MEDLINE®/PubMed and Scopus databases were searched with additional integration from external sources, between March and April 2020. To meet the inclusion criteria, studies published from 2000 to 2020 that evaluated the impact of strategies and/or tactics on cycling performance or aimed to study and develop strategy and/or tactic models to improve cycling performance were selected. EVIDENCE SYNTHESIS: Starting from the 12972 identified records, totally 22 studies met the inclusion criteria and were included in the current systematic review. Studies emerged from the selection focused mainly on time trials strategies analysis (54.55%), track cycling strategy analysis (22.73%) and other cycling disciplines strategy evaluation (road cycling, mountain bike, cyclocross; 22.73%). According to the studies' objectives, four main topics of investigation emerged from the research: evaluation of the impact of different starting strategies on time-trial performance; evaluation of different pacing strategies on performance; evaluation of aerodynamics and drag coefficients according to racing strategy in team pursuit; application of video analysis or strategy/tactics effect on performance. CONCLUSIONS: Strategy and tactics analysis in cycling represent a key additional performance variable to add to the traditionally more studied and analyzed parameters. However, few studies deeply analyzed these variables. Future works may focus on these aspects to investigate strategy and tactics insights and application of evaluation methods in cycling.

Performance, balance and posture variations with Occlusal Splint and Taopatch® devices: a retrospettive cross-over study.

BACKGROUND: The aim of the study was to evaluate how muscular performances, balance and posture were influenced applying Occlusal Splints and Taopatch® 8 (Tao Technologies Srls, Cittadella, Padua, Italy) devices in athletes. METHODS: Eighteen athletes, 7 females and 11 males, with an average age of 23.8 years, were included. Two devices were used: 1) a customized soft occlusal splint to be applied to the lower ach; 2) nanotechnological devices based on carbon nanotubules and quantum dots (Taopatch®) positioned on C7 and xiphoid process. Four functional tests were performed: surface electromyography (sEMG), kinesiography, the squat jump and counter movement jump and handgrip test. The tests were performed in the following order: at the baseline (no treatments), and after having applied the bite alone, the occlusal splint and Taopatch® devices together and the Taopatch® devices alone. RESULTS: The sEMG showed an increased maximum clenching voltage in respect of the baseline for all treatments that included the occlusal splint. The kinesiography showed an improvement of the movements of the occlusal muscles. The squat jump increased the height of 10-14 mm, the best results registered with the bite. The handgrip showed an increased strength, that was higher with the bite and the Taopatch® devices used alone (~5 lbs.). CONCLUSIONS: The use of an occlusal splint and Taopatch® devices use alone or in conjunction immediately influenced strength and balance of the occlusal postural muscles.