Gymnastik- och idrottshögskolan, GIH

The study aimed to identify a small set of fitness tests that could effectively predict performance in simulated firefighting tasks. Thirty-six (25 male and 11 female) firefighters participated in the study. Strength was evaluated with grip strength, barbell bench rows, and elevated trap bar deadlifts. Work capacity was assessed using a 3-minute pyramid test, executed with and without firefighting equipment. Firefighting performance was evaluated using a simulated work task course comprising stair climbing, hose pull, victim rescue, and equipment carry. We used backward linear regressions to derive models incorporating fitness test results, demographic variables, and oxygen uptake measures as predictors. Statistical significance was set to p < 0.05. The pyramid test without equipment accounted for 59% of the variance in task performance. When body mass and height were included, the model's predictive power increased to 71%. A final model, integrating the pyramid test, body mass, and absolute maximal oxygen uptake capacity (V̇o2max), explained 81% of performance variation. Our findings indicate that V̇o2max is the key factor in firefighter task performance, explaining 69% of the variance. The pyramid test, which estimates V̇o2max and predicted 59% of performance, is simple, time efficient, and can be conducted at stations to assess physical ability and work capacity. Incorporating the pyramid test into regular assessments can help firefighters focus on improving their work capacity, which is essential for achieving better performance.

This study aimed to investigate the effect of intrasession exercise order of maximal effort flywheel resistance training (RT; 436 repetitions [rep]) and high-intensity interval training (HIIT, 2–438 rep of 20 second at 130% of Watt atV̇O2max [wV̇O2max]), on the development of maximal strength and power in elite team-sport athletes. A 7-week training intervention involving 2 training sessions per week of either HIIT followed by RT (HIIT + RT, n 5 8), RT followed by HIIT (RT + HIIT, n 5 8), or RTalone (RT, n 5 7) was conducted in 23 elite male bandy players (24.7 6 4.3 years). Power and work were continuously measured during the flywheel RT. Isometric squat strength (ISq), countermovement jump, squat jump, and V̇O2max were measured before and after the training period. Power output during training differed between the groups (p 5 0.013, h2p5 0.365) with RT producing more power than HIIT + RT (p 5 0.005). ISq improved following RT + HIIT (;80%, d 5 2.10, p 5 0.001) and following HIIT + RT(;40%, d 5 1.64, p 5 0.005), and RT alone (;70%, d 5 1.67, p 5 0.004). V̇O2max increased following RT + HIIT and HIIT + RT(;10%, d51.98, p50.001 resp. d52.08, p50.001). HIIT before RT reduced power output during RT in elite team-sport athletes but did not lead to blunted development of maximal strength or power after a 7-week training period. During longer training periods(.7-weeks), it may be advantageous to schedule RT before HIIT because the negative effect of HIIT + RT on training quality increased during the final weeks of training. In addition, the largest training effect on maximal strength was observed following RT +HIIT.

Räddningsregion Östra Svealand (RRÖS) initierade i januari 2021 ett arbete för att: (i) hitta gemensamma grunder gällande tester och krav i samband med rekrytering, (ii) skapa samsyn kring de årliga fysiska testerna och (iii) skapa riktlinjer för fysträning.<BR><BR>

RRÖS har i samband med detta vänt sig till Gymnastik och idrottshögskolan för att arbeta fram relevanta tester som kan användas för att följa upp och utveckla medarbetarna fysiskt. GIH:s uppdrag har begränsats till delprojektet; fysiska tester. Målet för detta delprojekt var att ta fram tester med hög validitet och reliabilitet för kondition, styrka och rörlighet. Det var också viktigt att testerna kunde användas för utvärdering på individuell nivå samt kunna genomföras på stationerna utan dyr eller avancerad utrustning.

PURPOSE: This study compared the effects of heavy resisted sprint training (RST) versus unresisted sprint training (UST) on sprint performance among adolescent soccer players.

METHODS: Twenty-four male soccer players (age: 15.7 [0.5] y; body height: 175.7 [9.4] cm; body mass: 62.5 [9.2] kg) were randomly assigned to the RST group (n = 8), the UST group (n = 10), or the control group (n = 6). The UST group performed 8 × 20 m unresisted sprints twice weekly for 4 weeks, whereas the RST group performed 5 × 20-m heavy resisted sprints with a resistance set to maximize the horizontal power output. The control group performed only ordinary soccer training and match play. Magnitude-based decision and linear regression were used to analyze the data.

RESULTS: The RST group improved sprint performances with moderate to large effect sizes (0.76-1.41) across all distances, both within and between groups (>92% beneficial effect likelihood). Conversely, there were no clear improvements in the UST and control groups. The RST evoked the largest improvements over short distances (6%-8%) and was strongly associated with increased maximum horizontal force capacities (r = .9). Players with a preintervention deficit in force capacity appeared to benefit the most from RST.

CONCLUSIONS: Four weeks of heavy RST led to superior improvements in short-sprint performance compared with UST among adolescent soccer players. Heavy RST, using a load individually selected to maximize horizontal power, is therefore highly recommended as a method to improve sprint acceleration in youth athletes.

Physical characteristics of elite male bandy players have not been studied for the last 30 years. Therefore, the purpose of this study was to evaluate the physical characteristics of elite male bandy players with respect to playing positions. A cross-sectional study was performed that included 25 male bandy players from one of the highest-ranked bandy leagues in the world. Body weight, length, isometric mid-thigh pull, countermovement jump, squat jump, unilateral long jump, bilateral long jump, 15- and 30-m sprint, 15-m flying sprint, and VO_2max were tested. Players were divided into forwards, midfielders, and defenders. Forwards had significantly (p = 0.012) higher relative VO_2max than defenders (59.8 ± 4.3 compared to 53.0 ± 5.6 mL/kg/min). No significant differences for any of the other measurements were observed between positions. This is the first study to present the physical characteristics between playing positions in off- and on-ice tests for male bandy players competing at the highest level. Today's bandy players are heavier and have lower relative VO_2max compared with players in the early 1990s. However, their work capacities have increased since their absolute VO_2max is higher. These results provide benchmark values that can serve as a foundation for strength and conditioning professionals when designing future training programs.

This study examines the association between aerobic capacity and biomarkers of skeletal- and cardiac muscle damage among amateur triathletes after a full distance Ironman. Men and women (N = 55) were recruited from local sport clubs. One month before an Ironman triathlon, they conducted a 20 m shuttle run test to determine aerobic capacity. Blood samples were taken immediately after finishing the triathlon, and analyzed for cardiac Troponin T (cTnT), Myosin heavy chain-a (MHC-a), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), Creatin Kinas (CK), and Myoglobin. Regression models examining the association between the biomarkers and aerobic capacity expressed in both relative terms (mLO2*kg^-1*min^-1) and absolute terms (LO2*min^-1) controlled for weight were fitted. A total of 39 subjects (26% females) had complete data and were included in the analysis. No association between aerobic capacity and cardiac muscle damage was observed. For myoglobin, adding aerobic capacity (mLO2*kg^-1*min^-1) increased the adjusted r² from 0.026 to 0.210 (F: 8.927, p = 0.005) and for CK the adjusted r² increased from -0.015 to 0.267 (F: 13.778, p = 0.001). In the models where aerobic capacity was entered in absolute terms the adjusted r² increased from 0.07 to 0.227 (F: 10.386, p = 0.003) for myoglobin and for CK from -0.029 to 0.281 (F: 15.215, p < 0.001). A negative association between aerobic capacity and skeletal muscle damage was seen but despite the well-known cardio-protective health effect of high aerobic fitness, no such association could be observed in this study.

BACKGROUND: While overall physical activity is clearly associated with a better short-term and long-term health, prolonged strenuous physical activity may result in a rise in acute levels of blood-biomarkers used in clinical practice for diagnosis of various conditions or diseases. In this study, we explored the acute effects of a full Ironman-distance triathlon on biomarkers related to heart-, liver-, kidney- and skeletal muscle damage immediately post-race and after one week's rest. We also examined if sex, age, finishing time and body composition influenced the post-race values of the biomarkers. METHODS: A sample of 30 subjects was recruited (50% women) to the study. The subjects were evaluated for body composition and blood samples were taken at three occasions, before the race (T1), immediately after (T2) and one week after the race (T3). Linear regression models were fitted to analyse the independent contribution of sex and finishing time controlled for weight, body fat percentage and age, on the biomarkers at the termination of the race (T2). Linear mixed models were fitted to examine if the biomarkers differed between the sexes over time (T1-T3). RESULTS: Being male was a significant predictor of higher post-race (T2) levels of myoglobin, CK, and creatinine levels and body weight was negatively associated with myoglobin. In general, the models were unable to explain the variation of the dependent variables. In the linear mixed models, an interaction between time (T1-T3) and sex was seen for myoglobin and creatinine, in which women had a less pronounced response to the race. CONCLUSION: Overall women appear to tolerate the effects of prolonged strenuous physical activity better than men as illustrated by their lower values of the biomarkers both post-race as well as during recovery.

Recently, molecular motor gliding assays with actin and myosin from muscle have been realized on semiconductor nanowires coated with Al2O3. This opens for unique nanotechnological applications and novel fundamental studies of actomyosin motor function. Here, we provide a comparison of myosin-driven actin filament motility on Al2O3 to both nitrocellulose and trimethylchlorosilane derivatized surfaces. We also show that actomyosin motility on the less than 200 nm wide tips of arrays of Al2O3-coated nanowires can be used to control the number, and density, of myosin-actin attachment points. Results obtained using nanowire arrays with different inter-wire spacing are consistent with the idea that the actin filament sliding velocity is determined both by the total number and the average density of attached myosin heads along the actin filament. Further, the results are consistent with buckling of long myosin-free segments of the filaments as a factor underlying reduced velocity. On the other hand, the findings do not support a mechanistic role in decreasing velocity, of increased nearest neighbor distance between available myosin heads. Our results open up for more advanced studies that may use nanowire-based structures for fundamental investigations of molecular motors, including the possibility to create a nanowire-templated bottom-up assembly of 3D, muscle-like structures.

Semiconductor nanowire arrays offer significant potential for biosensing applications with optical read-out due to their high surface area and due to the unique optical properties of one-dimensional materials. A challenge for optical read-out of analyte-binding to the nanowires is the need to efficiently collect and detect light from a three-dimensional volume. Here we show that light from fluorophores attached along Several mu m long vertical Al2O3 coated gallium phosphide nanowires couples into the wires, is guided along them and emitted at the tip. This enables effective collection of light emitted by fluorescent analytes located at different focal planes along the nanowire. We unequivocally demonstrate the light-guiding effect using a novel method whereby the changes in emitted fluorescence intensity are observed when fluorescent cytoskeletal filaments are propelled by molecular motors along the wires. The findings are discussed in relation to nanobiosensor developments, other nanotechnological applications, and fundamental studies of motor function.