Monitoring Changes in Lower-Limb Strength and Power in Elite Athletes With the Countermovement-Jump and Keiser Leg-Press Tests.

PURPOSE: To determine the utility of countermovement-jump and Keiser leg-press tests for tracking changes in elite athletes of different sports. METHODS: Elite athletes of the Norwegian Olympic Federation (126 individuals from 18 sports) performed countermovement-jump and Keiser tests on 2 to 11 occasions between 2014 and 2021. Separate analyses were performed for male and female alpine skiing, male and female handball, male ice hockey, and males and females of other sports. Means and standard deviations of consecutive change scores were combined with short-term error of measurement (3.7%-7.0%) and smallest important changes (2.0%-3.6%, defined by standardization) to determine the proportions of athletes who experienced decisive changes in 2 senses: first, the athlete did not get substantially worse or better (>90% chance of either), and second, the athlete did get substantially worse or better (>90% chance of either). RESULTS: Averaged over sports, Keiser peak power and relative peak power had the highest proportions of decisive changes in the first (60% and 55%) and second senses (25% and 28%). The velocity intercept of the force-velocity relationship had the lowest proportions in the first and second senses (29% and 11%), while jump height, Keiser mean power, relative mean power, the force intercept, and the slope of the force-velocity relationship had similar proportions (40%-53% and 15%-21%). CONCLUSIONS: With the possible exception of the Keiser test velocity intercept, the proportions of observed decisive changes in elite athletes using Keiser measures and countermovement-jump height between tests appear adequate for the measures to be useful for routine monitoring.

Altered Sympathoadrenal Activity Following Cold-Water Diving.

INTRODUCTION: Little data exist on the effect of extremely cold-water diving on thermo-metabolic hormone secretion. Moreover, the impact of repetitive dives on the stress response is unknown. The purpose of this study was to determine the effects of two daily bouts of cold-water diving on the hormonal and metabolic profile of elite military personnel and to measure the stress response. METHODS: Healthy, male, Norwegian Special Forces operators (n = 5) volunteered for this study. Physiological and hormone data were analyzed prior to and following twice-daily Arctic dives (3.3°C). RESULTS: Core temperature was maintained (p > .05), whereas skin temperature was significantly reduced over the course of each dive (p < .01). Pairwise comparisons revealed adrenocorticotropic hormone (ACTH) and cortisol concentration significantly decreased across both dives and days (p < .001). Adrenaline and noradrenaline significantly increased across both time and day (p < .001). Leptin, testosterone, and IGF-1 significantly decreased over time but recovered between days. CONCLUSION: The main findings of this effort are that there is a rapid sympathetic-adreno-medullary (SAM/SNS) response to cold-water diving and a suppression of the hypothalamic-pituitary-adrenal (HPA) axis and hormones related to repair and recovery. While the sample size was too small to determine the role of SAM/SNS, HPA, and thyroid hormone effect on thermoregulation, it addresses a gap in our understanding of physiological adaptions that occurs in extreme environments.

Factors associated with high-level endurance performance: An expert consensus derived via the Delphi technique.

There is little agreement on the factors influencing endurance performance. Endurance performance often is described by surrogate variables such as maximum oxygen consumption, lactate threshold, and running economy. However, other factors also determine success and progression of high-level endurance athletes. Therefore, the aim was to identify the relevant factors for endurance performance assessed by international experts by adhering to a structured communication method (i.e., Delphi technique). Three anonymous evaluation rounds were conducted initiated by a list of candidate factors (n = 120) serving as baseline input variables. The items that achieved ≥70% of agreement in round 1 were re-evaluated in a second round. Items with a level of agreement of ≥70% in round 2 reached consensus and items with a level of agreement of 40-69% in round 2 were re-rated in a third round followed by a consensus meeting. Round 1 comprised of 27 panellists (n = 24 male) and in round 2 and 3 18 (n = 15 male) of the 27 panellists remained. Thus, the final endurance expert panel comprised of 18 international experts (n = 15 male) with 20 years of experience on average. The consensus report identified the following 26 factors: endurance capacity, running economy, maximal oxygen consumption, recovery speed, carbohydrate metabolism, glycolysis capacity, lactate threshold, fat metabolism, number of erythrocytes, iron deficiency, muscle fibre type, mitochondrial biogenesis, hydrogen ion buffering, testosterone, erythropoietin, cortisol, hydration status, vitamin D deficiency, risk of non-functional overreaching and stress fracture, healing function of skeletal tissue, motivation, stress resistance, confidence, sleep quality, and fatigue. This study provides an expert-derived summary including 26 key factors for endurance performance, the "FENDLE" factors (FENDLE = Factors for ENDurance Level). This consensus report may assist to optimize sophisticated diagnostics, personalized training strategies and technology.

Impact of a 10,000-m Cold-Water Swim on Norwegian Naval Special Forces Recruits.

BACKGROUND: Special Operation Forces (SOF) operate regularly in extreme environmental conditions that may affect tactical and physical performance. The main aims of the present study were to elucidate the impact of a long cold-water swim on SOF recruits' dexterity, performance, and reaction time. MATERIAL AND METHODS: Eleven recruits from Norwegian Naval Special Operation Command (NORNAVSOC) that were participating in a 10,000-m open water swim with a dry suit in 5°C cold water volunteered to participate in this study. The exercise was part of their training. Grip strength, lower body power, and dexterity were measured before, immediately after, and 24 hours after the swim. In addition, core and skin temperatures were measured continuously during the swim and until 45 minutes after the swim. RESULTS: After the swim, moderate to large reductions in core temperature, lower body power, and reaction time were observed. Moreover, very large to extremely large reductions in skin temperature, grip strength, and dexterity were also observed. CONCLUSION: These results demonstrate that exposure to a 10,000-m swim in 5°C water using standard equipment led to a significant drop in the recruits' temperature and performance. These findings could have a meaningful impact on the planning of training, operations, and gear used for SOF.

Peak Age and Performance Progression in World-Class Weightlifting and Powerlifting Athletes.

PURPOSE: To quantify age of peak performance and performance improvements in the years preceding peak age in elite weightlifting and powerlifting athletes using results from powerlifting World Championships in 2003-2017 and weightlifting World Championships and Olympic Games in 1998-2017. METHODS: Individual performance trends were derived by fitting a quadratic curve separately to each athlete's performance and age data. Effects were evaluated using magnitude-based inferences. RESULTS: Peak age (mean [SD]) was 35 (7) y for powerlifters and 26 (3) y for weightlifters, a large most likely substantial difference of 9, ±1 y (mean, 90% confidence limit). Men showed possibly higher peak age than women in weightlifting (0.8, ±0.7 y; small) and a possibly lower peak age in powerlifting (1.3, ±1.8 y; trivial). Peak age of athletes who ever won a medal was very likely less than that of nonmedalists in weightlifting (1.3, ±0.6 y; small), while the difference in powerlifters was trivial but unclear. Five-year improvements prior to peak age were 12% (10%) for powerlifters and 9% (7%) for weightlifters, a small possibly substantial difference (2.9, ±2.1%). Women exhibited possibly greater improvements than men in powerlifting (2.7, ±3.8%; small) and very likely greater in weightlifting (3.5, ±1.6%; small). Medalists possibly improved less than nonmedalists among powerlifters (-1.7, ±2.3%; small), while the difference was likely trivial for weightlifters (2.3, ±1.8%). CONCLUSION: These novel insights on performance development will be useful for practitioners evaluating strategies for achieving success.

Eccentric cycling does not improve cycling performance in amateur cyclists.

Eccentric cycling training induces muscle hypertrophy and increases joint power output in non-athletes. Moreover, eccentric cycling can be considered a movement-specific type of strength training for cyclists, but it is hitherto unknown if eccentric cycling training can improve cycling performance in trained cyclists. Twenty-three male amateur cyclists were randomized to an eccentric or a concentric cycling training group. The eccentric cycling was performed at a low cadence (~40 revolution per minute) and the intensity was controlled by perceived effort (12-17 on the Borgs scale) during 2 min intervals (repeated 5-8 times). The cadence and perceived effort of the concentric group matched those of the eccentric group. Additionally, after the eccentric or concentric cycling, both groups performed traditionally aerobic intervals with freely chosen cadence in the same session (4-5 x 4-15 min). The participants trained twice a week for 10 weeks. Maximal oxygen uptake (VO2max), maximal aerobic power output (Wmax), lactate threshold, isokinetic strength, muscle thickness, pedaling characteristics and cycling performance (6- and 30-sec sprints and a 20-min time trial test) were assessed before and after the intervention period. Inferences about the true value of the effects were evaluated using probabilistic magnitude-based inferences. Eccentric cycling induced muscle hypertrophy (2.3 ± 2.5% more than concentric) and augmented eccentric strength (8.8 ± 5.9% more than concentric), but these small magnitude effects seemed not to transfer into improvements in the physiological assessments or cycling performance. On the contrary, the eccentric training appeared to have limiting or detrimental effects on cycling performance, measured as Wmax and a 20-min time trial. In conclusion, eccentric cycling training did not improve cycling performance in amateur cyclists. Further research is required to ascertain whether the present findings reflect an actual lack of efficacy, negative effects or a delayed response to eccentric cycling training.

Depressed Physical Performance Outlasts Hormonal Disturbances after Military Training.

INTRODUCTION: The aim of this study was to investigate the effect of an arduous 1-wk military course on measures of physical performance, body composition, and blood biomarkers. METHODS: Participants were apprentices in an annual selection course for the Norwegian Special Forces. Fifteen soldiers (23 ± 4 yr, 1.81 ± 0.06 m, 78 ± 7 kg) completed a hell week consisting of rigorous activity only interspersed by 2 to 3 h of sleep per day. Testing was conducted before and 0, 1, 3, 7, and 14 d after the hell week. Physical performance was measured as muscle strength and jump performance. Body composition was measured by bioelectrical impedance and blood samples were collected and analyzed for hormones, creatine kinase, and C-reactive protein. RESULTS: Body mass was reduced by 5.3 ± 1.9 kg during the hell week and returned to baseline within 1 wk. Fat mass was reduced by 2.1 ± 1.7 kg and muscle mass by 1.9 ± 0.9 kg. Muscle strength in leg press and bench press was reduced by 20% ± 9% and 9% ± 7%, respectively, and both were approximately 10% lower than baseline after 1 wk of recovery. Jump-height was reduced by 28% ± 13% and was still 14% ± 5% below baseline after 2 wk of recovery. Testosterone was reduced by 70% ± 12% and recovered gradually within a week. Cortisol was increased by 154% ± 74% and did not fully recover during the next week. Insulin-like growth factor 1 was reduced by 51% ± 10% and triiodothyronine and thyroxine by 12% to 30%, all recovered within a week. CONCLUSIONS: One-week arduous military exercise resulted in reductions in body mass and performance, as well as considerable hormonal disturbances. Our most important observation was that whereas the hormonal systems was normalized within 1 wk of rest and proper nutrition, lower body strength and jump performance were still depressed after 2 wk.

Peak Age and Performance Progression in World-Class Track-and-Field Athletes.

The aim of this study was to quantify peak age and improvements over the preceding years to peak age in elite athletic contestants according to athlete performance level, sex, and discipline. Individual season bests for world-ranked top 100 athletes from 2002 to 2016 (14,937 athletes and 57,049 individual results) were downloaded from the International Association of Athletics Federations' website. Individual performance trends were generated by fitting a quadratic curve separately to each athlete's performance and age data using a linear modeling procedure. Mean peak age was typically 25-27 y, but somewhat higher for marathon and male throwers (∼28-29 y). Women reached greater peak age than men in the hurdles and middle- and long-distance running events (mean difference, ±90% CL: 0.6, ±0.3 to 1.9, ±0.3 y: small to moderate). Male throwers had greater peak age than corresponding women (1.3, ±0.3 y: small). Throwers displayed the greatest performance improvements over the 5 y prior to peak age (mean [SD]: 7.0% [2.9%]), clearly ahead of jumpers, long-distance runners, hurdlers, middle-distance runners, and sprinters (3.4, ±0.2% to 5.2, ±0.2%; moderate to large). Similarly, top 10 athletes showed greater improvements than top 11-100 athletes in all events (1.0, ±0.9% to 1.8, ±1.1%; small) except throws. Women improved more than men in all events (0.4, ±0.2% to 2.9, ±0.4%) except sprints. This study provides novel insight on performance development in athletic contestants that are useful for practitioners when setting goals and evaluating strategies for achieving success.

Validity, Reliability, and Performance Determinants of a New Job-Specific Anaerobic Work Capacity Test for the Norwegian Navy Special Operations Command.

Operators in Special Operation Forces (SOF) have a particularly demanding profession where physical and psychological capacities can be challenged to the extremes. The diversity of physical capacities needed depend on the mission. Consequently, tests used to monitor SOF operators' physical fitness should cover a broad range of physical capacities. Whereas tests for strength and aerobic endurance are established, there is no test for specific anaerobic work capacity described in the literature. The purpose of this study was therefore to evaluate the reliability, validity, and to identify performance determinants of a new test developed for testing specific anaerobic work capacity in SOF operators. Nineteen active young students were included in the concurrent validity part of the study. The students performed the evacuation (EVAC) test 3 times and the results were compared for reliability and with performance in the Wingate cycle test, 300-m sprint, and a maximal accumulated oxygen deficit (MAOD) test. In part II of the study, 21 Norwegian Navy Special Operations Command operators conducted the EVAC test, anthropometric measurements, a dual x-ray absorptiometry scan, leg press, isokinetic knee extensions, maximal oxygen uptake test, and countermovement jump (CMJ) test. The EVAC test showed good reliability after 1 familiarization trial (intraclass correlation = 0.89; coefficient of variance = 3.7%). The EVAC test correlated well with the Wingate test (r = -0.68), 300-m sprint time (r = 0.51), and 300-m mean power (W) (r = -0.67). No significant correlation was found with the MAOD test. In part II of the study, height, body mass, lean body mass, isokinetic knee extension torque, maximal oxygen uptake, and maximal power in a CMJ was significantly correlated with performance in the EVAC test. The EVAC test is a reliable and valid test for anaerobic work capacity for SOF operators, and muscle mass, leg strength, and leg power seem to be the most important determinants of performance.

A 1-year follow-up of effects of exercise programs on well-being in older adults.

PURPOSE: The purpose of this study was to investigate the long-term effects of three types of training on wellbeing and frequency of physical activity and to determine whether preintervention motivation moderates the effects. METHODS: Sixty-two older adults (M = 75 years old, SD = 5; 61% women) completed 4-mo programs of endurance, functional or strength training, with reassessment of well-being (life satisfaction, positive affect, negative affect, vitality) and physical activity 12 mo later. RESULTS: All groups showed small improvements in most measures of well-being at 4 mo. At follow-up, endurance training still had small beneficial effects, while changes with functional and strength training were generally trivial or harmful. Analysis for moderators indicated that autonomously motivated individuals better maintained gains in well-being and had higher frequencies of physical activity at follow-up compared with controlled individuals. CONCLUSION: Endurance training is recommended for older adults, but the long-term outcomes depend on the individual's motivational regulation at commencement.