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The combination of high volume of moderate-intensity continuous training with a low volume of high-intensity interval training improved body composition and physical capacities in individuals with obesity. However, polarized training (POL) has never been used in adult men with obesity. Thus, the purpose of this study was to investigate changes in body composition and physical capacities induced by a 24-week POL or threshold (THR) program in obese male adults. Twenty male patients (mean age 39.8±6.3 yrs; mean body mass index [BMI] 31.6±2.7 kg∙m-2) participated in this study (n: 10 POL, n: 10 THR). After 24-week, body mass (BM) and fat mass (FM) decreased by -3.20±3.10 kg (P<0.05) and -3.80±2.80 kg (P<0.05), respectively, similarly in both groups. Maximal oxygen uptake ( ̇VO2max) and ̇VO2 at respiratory compensation point (RCP) increased in the POL group (+8.5±12.2 and+9.0±17.0%, P<0.05) and in the THR group (+4.24±8.64 and+4.0±6.70%, P<0.05), as well ̇VO2 at gas exchange threshold (GET) increased similarly in both groups (+12.8±12.0%, P<0.05). POL and THR were equally effective in improving body composition and physical capacities in obese subjects. Future studies are needed to determine whether adherence to the training program can be improved by adding a running competition compared with a group without competition at the end of the training program.

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PURPOSE: In sky- and trail-running competitions, many athletes use poles. The aims of this study were to investigate whether the use of poles affects the force exerted on the ground at the feet (Ffoot), cardiorespiratory variables and maximal performance during uphill walking. METHODS: Fifteen male trail runners completed four testing sessions on different days. On the first two days, they performed two incremental uphill treadmill walking tests to exhaustion with (PWincr) and without poles (Wincr). On the following days, they performed submaximal and maximal tests with (PW80 and PWmax) and without (W80 and Wmax) poles on an outdoor trail course. We measured cardiorespiratory parameters, the rating of perceived exertion, the axial poling force and Ffoot. RESULTS: When walking on the treadmill, we found that poles reduced maximum Ffoot (- 2.8 ± 6.4%, p = 0.03) and average Ffoot (- 2.4 ± 3.3%, p = 0.0089). However, when outdoors, we found pole effect only for average Ffoot (p = 0.0051), which was lower when walking with poles (- 2.6 ± 3.9%, p = 0.0306 during submaximal trial and - 5.21 ± 5.51%, p = 0.0096 during maximal trial). We found no effects of poles on cardiorespiratory parameters across all tested conditions. Performance was faster in PWmax than in Wmax (+ 2.5 ± 3.4%, p = 0.025). CONCLUSION: The use of poles reduces the foot force both on the treadmill and outdoors at submaximal and maximal intensities. It is, therefore, reasonable to conclude that the use of poles "saves the legs" during uphill without affecting the metabolic cost.

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Obesity and related metabolic diseases represent a worldwide health problem. The main factor predisposing to obesity is an unhealthy lifestyle including the lack of physical activity. A pivotal role in the etio-pathogenesis of obesity is carried out by adipose tissue, an endocrine organ secreting several adipokines involved in numerous metabolic and inflammatory processes. Among these, of particular importance is adiponectin, an adipokine involved in the regulation of insulin sensibility and in anti-inflammatory processes. The aim of the study was to determine the effects of 24 weeks of two different training programs polarized (POL) and threshold training (THR) on body composition, physical capacities and adiponectin expression. Thirteen male obese subjects (BMI: 32.0 ± 3.0 kg m-2) followed 24 weeks of two different training programs, POL and THR, consisting of walking or running (or a combination of the two methods) in their normal living conditions. Before (T0) and after the end of the program (T1), the assessment of body composition was assessed by bioelectrical impedance and the concentration of salivary and serum adiponectin was analyzed by enzyme-linked immunosorbent assay and western blotting. Although the results obtained did not show significant differences between the two training programs, body mass and body mass index decreased by a mean of -4.46 ± 2.90 kg and 1.43 ± 0.92 kg m-2 (P < 0.05). Fat mass decreased by -4.47 ± 2.78 kg (P < 0.05). V'O2max increased by a mean of 0.20 ± 0.26 L min-1 (P < 0.05) Also, we observed an increase in saliva and in serum of adiponectin concentrations at T1 compared to T0 by 4.72 ± 3.52 µg mL-1 and 5.22 ± 4.74 ng mL-1 (P < 0.05) respectively. Finally, we found significant correlations between Δ serum adiponectin and Δ Hip (R = -0.686, P = 0.001) and between Δ salivary adiponectin and ΔWaist (R = -0.678, P = 0.011). Our results suggest that a 24 weeks training program, independently from intensity and volume, induces an amelioration of body composition and fitness performance. These improvements are associated with an increase in total and HMW adiponectin expression in both saliva and in serum.

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Background: /Objectives: A weekly combination of a high volume of moderate-intensity continuous training (MICT) with a low volume of high-intensity interval training (HIIT) provides important improvements in body composition and physical capacities in individuals with obesity. However, previous studies did not determine the weekly proportions of HIIT and MICT a priori. This study aimed to investigate changes in body composition, physical capacities and the fat oxidation rate in obese male adults by comparing a combination of MICT and HIIT, called combined training (COMB), with HIIT for a 12-week period. Methods: Thirty-four obese male adults (mean age: 39.4 ± 7.0 y; mean body mass index [BMI] 34.0 ± 4.2 kg m-2) participated in this study (n = 18 for COMB, n = 16 HIIT), attending âˆ¼ 36 training sessions. The COMB group performed 3 repetitions of 2 min at 95% of peak oxygen uptake (V'O2 peak) (e.g., HIIT ≤20%), followed by 30 min at 60% of VO2 peak (e.g., MICT ≥80%). The HIIT group performed 5-7 repetitions of 2 min at 95% of VO2 peak. At baseline (PRE) and at the end of the training period (POST), body composition, VO2 peak, and the fat oxidation rate were measured. The two training programs were equivalent in caloric expenditure. Results: At POST, body mass (BM) and fat mass (FM) decreased by a mean of 3.09 ± 3.21 kg and 3.90 ± 2.40 kg, respectively (P < 0.05), in both groups and V'O2 peak increased in both groups by a mean of 0.47 ± 0.34 L min-1 (P < 0.05). The maximal fat oxidation rate increased similarly in both groups from 0.32 ± 0.05 to 0.36 ± 0.06 g min-1 (P < 0.05). Conclusion: COMB training represents a viable alternative to HIIT to improve anthropometric characteristics, physical capacities and fat oxidation in obese male adults.

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PURPOSE: Accumulating the time near maximum aerobic power [Formula: see text] is considered to be the most effective way to improve aerobic capacity. The aims of this study were: (1) to verify whether postponing the first recovery interval improves time to exhaustion during a high-intensity interval training (HIIT) test, and (2) to verify whether a HIIT protocol with decreasing interval duration (HIDIT) is more effective in accumulating time near [Formula: see text] compared with two classical protocols with short intervals (SIHIIT) and long intervals (LIHIIT). METHODS: Nine active males (35 ± 11 years, [Formula: see text] 52 ± 5 mL·min-1·kg-1) performed a graded exercise test on an athletic track. Critical velocity and D' were estimated from three to five high-intensity trials to exhaustion. Then, the subjects performed three trials with a single recovery interval after 30 s (Rec30s), after 3 min (Rec3min) and after exhaustion (RecTlim) to verify whether postponing the first recovery interval enhances the time to exhaustion. Finally, the subjects performed the three HIIT protocols mentioned above. RESULTS: The time to exhaustion was significantly greater in RecTlim (464 ± 67 s) than in Rec3min (388 ± 48 s) (p < 0.0078) and Rec30s (308 ± 44 s) (p > 0.0001). Additionally, it was significantly greater in Rec3min than in Rec30s (p = 0.0247). Furthermore, the time accumulated near [Formula: see text] was significantly longer in HIDIT (998 ± 129 s) than in SIHIIT (678 ± 116 s) (p = 0.003) and LIHIIT (673 ± 115 s) (p < 0.031). CONCLUSIONS: During the trials, postponing the first recovery interval was effective in improving the time to exhaustion. Moreover, HIDIT was effective in prolonging the time near [Formula: see text].

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PURPOSE: The aim of this study was to compare pole walking (PW) and walking without poles (W) on a steep uphill mountain path (1.3 km, 433 m of elevation gain) at 2 different intensities: a maximal effort that would simulate a vertical kilometer intensity and a lower intensity (80% of maximal) simulating an ultratrail race. METHODS: On the first day, we tested the participants in the laboratory to determine their maximal physiological parameters, respiratory compensation point, and gas exchange threshold. Then, they completed 4 uphill tests along a mountain path on 4 separate days, 2 at their maximum effort (PWmax and Wmax, randomized order) and 2 at 80% of the mean vertical velocity maintained during the first 2 trials (PW80 and W80, randomized order). We collected metabolic data, heart rate, blood lactate concentration, and rating of perceived exertion at the end of each trial. We also collected rating of perceived exertion at every 100 m of elevation gain during PW80 and W80. RESULTS: Participants completed the maximal effort faster with poles versus without poles (18:51 [03:12] vs 19:19 [03:01] in min:s, P = .013, d = 0.08, small). Twelve of the 15 participants (80%) improved their performance when they used poles. During PW80 and W80, none of the physiological or biomechanical parameters were different. CONCLUSION: In the examined condition, athletes should use poles during steep uphill maximal efforts to obtain the best performance. Conversely, during submaximal effort, the use of poles does not provide advantages in uphill PW.

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PURPOSE: To compare energetics and spatiotemporal parameters of steep uphill pole walking on a treadmill and overground. METHODS: First, the authors evaluated 6 male trail runners during an incremental graded test on a treadmill. Then, they performed a maximal overground test with poles and an overground test at 80% (OG80) of vertical velocity of maximal overground test with poles on an uphill mountain path (length = 1.3 km, elevation gain = 433 m). Finally, they covered the same elevation gain using poles on a customized treadmill at the average vertical velocity of the OG80. During all the tests, the authors measured oxygen uptake, carbon dioxide production, heart rate, blood lactate concentration, and rate of perceived exertion. RESULTS: Treadmills required lower metabolic power (15.3 [1.9] vs 16.6 [2.0] W/kg, P = .002) and vertical cost of transport (49.6 [2.7] vs 53.7 [2.1] J/kg·m, P < .001) compared with OG80. Also, oxygen uptake was lower on a treadmill (41.7 [5.0] vs 46.2 [5.0] mL/kg·min, P = .001). Conversely, respiratory quotient was higher on TR80 compared with OG80 (0.98 [0.02] vs 0.89 [0.04], P = .032). In addition, rate of perceived exertion was higher on a treadmill and increased with elevation (P < .001). The authors did not detect any differences in other physiological measurements or in spatiotemporal parameters. CONCLUSIONS: Researchers, coaches, and athletes should be aware that steep treadmill pole walking requires lower energy consumption but same heart rate and rate of perceived exertion than overground pole walking at the same average intensity.

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BACKGROUND: This study aimed to evaluate the relationship between physical activity habits, physical performance and cognitive capacity in older adults' population of Italy and Slovenia. METHODS: Anthropometric characteristics and body composition bioelectrical impedance analysis were evaluated in 892 older adults (60-80 y). Aerobic capacity was measured using the 2-km walk test and handgrip and flexibility tests were performed. Physical activity habits and cognitive functions were evaluated by the Global-Physical-Activity-Questionnaires (GPAQ) and by Montreal-Cognitive-Assessment (MoCA) questionnaires, respectively. RESULTS: GPAQ scores were associated with lower BMI (r=-0.096; P=0.005), lower percentage of fat-mass (r=-0.138; P=0.001), better results in the 2-km walk test (r=-0.175; P=0.001) and a higher percentage of fat-free mass (r=0.138; P=0.001). We also evaluated that a higher MoCA Score correlates with age (r=-0.208; P=0.001), 2-km walk test (r=-0.166; P=0.001), waist-hip ratio (r=-0.200; P=0.001), resting heart-rate (r=-0.087; P=0.025) and heart-rate at the end of 2-km walk test (r=0.189; P=0.001). CONCLUSIONS: Older adults with a higher level of daily physical activity showed reduction in fat-mass and BMI, and higher aerobic fitness; these characteristics have a protection effect on cognitive function.

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In recent years, different companies have developed devices that estimate "running power". The main objective of this paper is to evaluate the effect of running speed on aerobic and running powers measured using force plates and by different devices. The second objective is to evaluate the relationship between aerobic power and running powers measured using force plates and by different devices. We enrolled 11 subjects in the study, they performed 5-min running trials at 2.22, 2.78, 3.33, 3.89 and 4.44 m/s respectively on a force-measuring treadmill while we collected metabolic data. We calculated running power as the dot product of ground reaction force and velocity of the centre of mass and compared it to the running power estimates of three devices: Skillrun (Technogym), Stryd Summit Powermeter (Stryd) and Garmin HRM-Run (Garmin). We found statistically significant linear correlations with running powers measured by all devices and running speed. Although absolute running power measurements were different among devices, an increase of 1 m/s in running speed translated to an increase of 0.944 W/kg in running power (p < 0.001). We found statistically significant linear correlations with running powers measured by all devices and aerobic power, in particular: as aerobic power increases by 1 W/kg, running power increases by 0.218 W/kg for all devices (p < 0.001). For level treadmill running, across speeds, running power measured by commercially available devices reflects force-based measurements and it can be a valuable metric, providing quasi real-time feedback during training sessions and competitions.HighlightsWe evaluated the effect of running speed on aerobic and running powers measured using force plates and by different devices.We also compared the relationship between aerobic power and running powers measured using force plates and by different devices.We found statistically significant linear correlations with running powers measured by all devices and aerobic power, in particular: as aerobic power increases by 1 W/kg, running power increases by 0.218 W/kg for all devices.For level treadmill running, across speeds, running power measured by commercially available devices reflects force-based measurements and it can be a valuable metric, providing quasi real-time feedback during training sessions and competitions.

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Downhill running has an important effect on performance in trail running competitions, but it is less studied than uphill running. The purpose of this study was to investigate the cardiorespiratory response during 15 min of downhill running (DR) and to evaluate the neuromuscular consequences in a group of trail runners. Before and after a 15-min DR trial (slope: -25%) at ~60% of maximal oxygen consumption (V̇O2max), we evaluated maximal voluntary contraction torque (MVCt) and muscle contractility in a group of seventeen trail running athletes. Additionally, during the DR trial, we measured V̇O2 and heart rate (HR). V̇O2 and HR increased as a function of time, reaching +19.8 ± 15.9% (p < 0.001; ES: 0.49, medium) and +15.3 ± 9.9% (p < 0.001; ES: 0.55, large), respectively, in the last minute of DR. Post-exercise, the MVCt decreased (-22.2 ± 12.0%; p < 0.001; ES = 0.55, large) with respect to the pre-exercise value. All the parameters related to muscle contractility were impaired after DR: the torque evoked by a potentiated high frequency doublet decreased (-28.5 ± 12.7%; p < 0.001; ES: 0.61, large), as did the torque response from the single-pulse stimulation (St, -41.6 ± 13.6%; p < 0.001; ES: 0.70, large) and the M-wave (-11.8 ± 12.1%; p < 0.001; ES: 0.22, small). We found that after 15 min of DR, athletes had a decreased MVCt, which was ascribed mainly to peripheral rather than central alterations. Additionally, during low-intensity DR exercise, muscle fatigue and exercise-induced muscle damage may contribute to the development of O2 and HR drift.

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PURPOSE: Neuromuscular Electrical Stimulation (NMES) is commonly used in neuromuscular rehabilitation protocols, and its parameters selection substantially affects the characteristics of muscle activation. Here, we investigated the effects of short pulse width (200 µs) and higher intensity (short-high) NMES or long pulse width (1000 µs) and lower intensity (long-low) NMES on muscle mechanical output and fractional oxygen extraction. Muscle contractions were elicited with 100 Hz stimulation frequency, and the initial torque output was matched by adjusting stimulation intensity. METHODS: Fourteen able-bodied and six spinal cord-injured (SCI) individuals participated in the study. The NMES protocol (75 isometric contractions, 1-s on-3-s off) targeting the knee extensors was performed with long-low or short-high NMES applied over the midline between anterior superior iliac spine and patella protrusion in two different days. Muscle work was estimated by torque-time integral, contractile properties by rate of torque development and half-relaxation time, and vastus lateralis fractional oxygen extraction was assessed by Near-Infrared Spectroscopy (NIRS). RESULTS: Torque-time integral elicited by the two NMES paradigms was similar throughout the stimulation protocol, with differences ranging between 1.4% (p = 0.877; able-bodied, mid-part of the protocol) and 9.9% (p = 0.147; SCI, mid-part of the protocol). Contractile properties were also comparable in the two NMES paradigms. However, long-low NMES resulted in higher fractional oxygen extraction in able-bodied (+ 36%; p = 0.006). CONCLUSION: Long-low and short-high NMES recruited quadriceps femoris motor units that demonstrated similar contractile and fatigability properties. However, long-low NMES conceivably resulted in the preferential recruitment of vastus lateralis muscle fibers as detected by NIRS.

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BACKGROUND: Participants in ultramarathon and multi-stage races are continuously increasing. A detailed knowledge of the time-course of the restoration in muscular, cardiac, and inflammatory biomarkers after a multi-stage race may help the design of training schedules focused to avoid adverse outcomes of repetitive high-intensity endurance exercise and athlete exhaustion. Thus, the aim of the study was to evaluate blood parameters and serum biomarkers associated to muscle damage and inflammation in athletes participating in a 3-stage competition. METHODS: Ten runners concluded the race "Magraid" consisting of 3 stages of 22, 48 and 20 km. Before (PRE), immediately after the end of the third stage (POST) and five days after the last stage (R5d), we collected blood samples. RESULTS: Among others, at POST mean white blood cell (+57±42%; P=0.006), blood urea nitrogen (+68±39%; P<0.001), creatinine (+17±12%, P=0.005), alanine aminotransferase (ALT, +104±69%; P=0.002), lactate dehydrogenase (LDH, +116±64%; P<0.001), creatine kinase (CK, +2044±1433%; P=0.011), CK-MBm (+1544±1007%; P=0.004), cardiac troponin I (cTnI, +85±129%; P=0.015), C-reactive protein (hsCRP, +2137±1660%; P=0.015) were higher than PRE. At R5d, ALT (+72±53%; P=0.010), LDH (+32±25%; P=0.006) and hsCRP (+252±234%; P=0.021) were still different compared with PRE. CONCLUSIONS: A 3-stage trail running race induces an inflammatory status and muscle damage and functional consequences on some physiological systems that may not be completely recovered within a short period.

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Off-road running continues to grow in popularity, with differing event categories existing, and terminologies are often used interchangeably and without precision. Trail running, mountain running, skyrunning, fell running, orienteering, obstacle course racing and cross-country running all take place predominantly in off-road terrain. Ultramarathon running refers to any running event over marathon distance conducted in any terrain and surface. Although some overlap may exist between these running events, mainly through the common denominator of off-road terrain, distinct features need to be recognised. As scientific interest in these activities grows, it becomes important to clarify these terms and develop a universal language for discussing these events. Similarly, off-road running athletes are generally not properly defined within the scientific literature, which makes intra- and inter-study comparisons difficult. The current position statement of the Ultra Sports Science Foundation highlights the different off-road running events and recommends clear reference to distance, surface, elevation change and altitude, type of event (continuous vs. staged), type of support, name and year of the event, governing body, and guidance on terminology. We further recommend to describe off-road running athletes by basic data, physiological determinants, training and competition characteristics in the scientific literature in order to facilitate and guide further research and practice.

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PURPOSE: to evaluate the effects of a trail-running race on muscle oxidative function by measuring pulmonary gas exchange variables and muscle fractional O2 extraction. METHODS: Eighteen athletes were evaluated before (PRE) and after (POST) a trail running competition of 32-km or 50-km with 2000 m or 3500 m of elevation gain, respectively. During the week before the race, runners performed an incremental uphill running test and an incremental exercise by utilizing a one-leg knee-extension (KE) ergometer. The KE exercise was repeated after the end of the race. During the KE test we measured oxygen uptake (V'O2) and micromolar changes in deoxygenated hemoglobin (Hb)+myoglobin (Mb) concentrations (Δ[deoxy(Hb+Mb)]) on vastus lateralis with a portable near-infrared spectroscopy. RESULTS: V'O2peak was lower at POST vs. PRE (-23.9±9.0%, p<0.001). V'O2peak at POST was lower than V'O2 at the same workload at PRE (-8.4±15.6%, p<0.050). Peak power output and time to exhaustion decreased at POST by -23.7±14.3% and -18.3±11.3%, respectively (p<0.005). At POST the increase of Δ[deoxy(Hb + Mb)] as a function of work rate, from unloaded to peak, was less pronounced (from 20.2±10.1 to 64.5±21.1% of limb ischemia at PRE to 16.9±12.7 to 44.0±18.9% at POST). Peak Δ[deoxy(Hb+Mb)] values were lower at POST (by -31.2±20.5%; p<0.001). CONCLUSIONS: trail running leads to impairment in skeletal muscle oxidative metabolism, possibly related to muscle damage from repeated eccentric contractions. In association with other mechanisms, the impairment of skeletal muscle oxidative metabolism is likely responsible of the reduced exercise capacity and tolerance during and following these races.

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Evaluation of cardiorespiratory parameters is important in athletic population in order to monitor the training status and define training intensities. The aim of this study was to validate an easy-to-perform running test called RABIT® (Running Advisor Billat Training) for detecting aerobic (AerT) and anaerobic (AnT) threshold and maximum parameters. Fifteen trained runners completed a graded (GRAD) and RABIT test (four self-selected pace steps: (i) 10 minutes at free warm-up pace, (ii) 5 minutes at medium pace, (iii) 3 minutes at hard pace, (iv) 10 minutes at easy pace). We compared the cardiorespiratory parameters and running speed of the RABIT with those corresponding to AerT, AnT or maximum parameters obtained by the GRAD. The ⩒O2max, HRmax, RERmax and running speed max measured during the 3-minute hard pace of the RABIT were not statistically different from the maximum parameters measured during GRAD (p > 0.05). The ⩒O2, HR and RER measured during the medium and easy pace of the RABIT were not significantly different from the AnT and AerT parameters measured during GRAD. In conclusion, RABIT was validated for all the maximum parameters and for most of Ant- and AerT-related parameters and then it might be used for detecting training zones in athletes.

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PURPOSE: In trail running and in uphill races many athletes use poles. However, there are few data about pole walking on steep uphill. The aim of this study was to compare the energy expenditure during uphill walking with (PW) and without (W) poles at different slopes. METHODS: Fourteen mountain running athletes walked on a treadmill in two conditions (PW and W) for 5 min at seven different angles (10.1°, 15.5°, 19.8°, 25.4°, 29.8°, 35.5° and 38.9°). We measured cardiorespiratory parameters, blood lactate concentration (BLa) and rating of perceived exertion (RPE). Then, we calculated the vertical cost of transport (CoTvert). Using video analysis, we measured stride frequency (SF) and stride length (SL). RESULTS: Compared to W, CoTvert during PW was lower at 25.4°, 29.8° and 35.5° PW ([Formula: see text] 2.55 ± 3.97%; [Formula: see text] 2.79 ± 3.88% and [Formula: see text] 2.00 ± 3.41%, p < 0.05). RPE was significantly lower during PW at 15.5°, 19.8°, 29.8°, 35.5° and 38.9° ([Formula: see text] 14.4 ± 18.3%; [Formula: see text] 16.2 ± 15.2%; [Formula: see text] 16.6 ± 16.9%; [Formula: see text] 17.9 ± 18.7% and [Formula: see text] 18.5 ± 17.8%, p < 0.01). There was no effect of pole use on BLa. However, BLa was numerically lower with poles at every incline except for 10.1°. On average, SF for PW was lower than for W ([Formula: see text] 6.7 ± 5.8%, p = 0.006) and SL was longer in PW than in W (+ 8.6 ± 4.5%, p = 0.008). CONCLUSIONS: PW on steep inclines was only slightly more economical than W, but the substantially lower RPE during PW suggests that poles may delay fatigue effects during a prolonged effort. We advocate for the use of poles during steep uphill walking, although the energetic savings are small.

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PURPOSE: Self-myofascial release (SMFR) is a type of self-massage that is becoming popular among athletes. However, SMFR's effects on running performance have not yet been investigated. The aim of this study was to evaluate the effects of SMFR on the cost of running (Cr). In addition, the authors evaluated the effects of SMFR on lower-limb muscle power. METHODS: Cr and lower-limb muscle power during squat jump (SJ) and countermovement jump (CMJ) were measured before (PRE), immediately after (POST), and 3 h after (POST 3h) an SMFR protocol (experimental condition). In the control-condition testing session, the same measurements were performed without undergoing the SMFR protocol. Experimental and control conditions were tested in a randomized order. RESULTS: Cr at POST trended to increase compared with PRE (+6.2% [8.3%], P = .052), whereas at POST 3h, Cr was restored to PRE values (+0.28% [9.5%], P = .950). In the experimental condition, no significant effect of time was observed for maximal power exerted during SJ. By contrast, maximal power exerted during CMJ at POST and at POST 3h was significantly higher than that observed at PRE (+7.9% [6.3%], P = .002 and +10.0% [8.7%], P = .004, respectively). The rate of force development measured during CMJ also increased after SMFR, reaching statistical significance at 200 ms from force onset at POST 3h (+38.9%, P = .024). CONCLUSIONS: An acute use of foam rollers for SMFR performed immediately prior to running may negatively affect endurance running performance, but its use should be added before explosive motor performances that include stretch-shortening cycles.

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BACKGROUND: Recent studies showed a positive effect of hydrogen rich water (HRW) intake on acid-base homeostasis at rest. We investigated 2-weeks of HRW intake on repeated sprint performance and acid-base status during prolonged intermittent cycling exercise. METHODS: In a cross over single-blind protocol, 8 trained male cyclists (age [mean±SD] 41±7 years, body mass 72.3±4.4 kg, height 1.77±0.04 m, maximal oxygen uptake [V̇O2max] 52.6±4.4 mL·kg-1·min-1) were provided daily with 2 liters of placebo normal water (PLA, pH 7.6, oxidation/reduction potential [ORP] +230 mV, free hydrogen content 0 ppb) or HRW (pH 9.8, ORP -180 mV, free Hydrogen 450 ppb). Tests were performed at baseline and after each period of 2 weeks of treatment. The treatments were counter-balanced and the sequence randomized. The 30-minute intermittent cycling trial consisted in 10 3-minute blocks, each one composed by 90 seconds at 40% V̇O2max, 60 seconds at 60% V̇O2max, 16 seconds all out sprint, and 14 seconds active recovery. Oxygen uptake (V̇O2), heart rate and power output were measured during the whole test, while mean and peak power output (PPO), time to peak power and Fatigue Index (FI) were determined during all the 16 seconds sprints. Lactate, pH and bicarbonate (HCO3-) concentrations were determined at rest and after each sprint on blood obtained by an antecubital vein indwelling catheter. RESULTS: In the PLA group, PPO in absolute values decreased significantly at the 8th and 9th of 10 sprints and in relative values, ΔPPO, decreased significantly at 6th, 8th and 9th of 10 sprints (by mean: -12±5%, P<0.006), while it remained unchanged in HRW group. Mean power, FI, time to peak power and total work showed no differences between groups. In both conditions lactate levels increased while pH and HCO3- decreased progressively as a function of the number of sprints. CONCLUSIONS: Two weeks of HRW intake may help to maintain PPO in repetitive sprints to exhaustion over 30 minutes.

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The aim of the study was to evaluate changes in cardiac troponin I levels (cTnI) and the main biomarkers of skeletal muscle damage after an uphill-only marathon, along with its relationship with athletes' physiological parameters. Twenty-two runners participated in the "Supermaratona dell'Etna" (43 km, 0-2850 m AMSL). Before and immediately after the race, body mass and hydration status were measured together with blood sampling. At the end of the race, mean cTnI increased significantly in all athletes (mean +900%), and in 52% of them the cTnI values were over the normal range. Mean creatinine and cortisol increased significantly (by 30.5% and 291.4%), while C-reactive protein levels did not change significantly. Then, an uphill-only marathon showed a significant increase in cardiac and skeletal muscle blood biomarkers of injury, and cTnI levels were not significantly correlated with age, body mass index, V̇O2max, training status, ultra-endurance training experience, race time and blood parameters.

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RESUMEN

PURPOSE: Vertical kilometer (VK) races, in which runners gain 1000 m of elevation in <5000 m of distance, are becoming popular. However, few studies on steep uphill running (>25°) exist. Previously, we determined that ~30° is the optimal angle for uphill running, costing the least amount of metabolic energy for a specific vertical velocity. To inform the training and strategy of VK racers, we quantified the metabolic cost of walking and running at various velocities up a 30° incline. METHODS: At 30°, 11 experienced runners (7 M, 4 F, 30.8 ± 7.9 years, 1.71 ± 0.08 m, 66.7 ± 9.4 kg) walked and ran for 5-min trials with 5-min rest between. Starting at 0.3 ms-1, we increased treadmill velocity by 0.1 ms-1 for each trial until subjects could not maintain the set velocity. We measured oxygen uptake (ml O2 kg-1 min-1) and metabolic power (W kg-1 = metabolic energy per unit time per unit body mass) and calculated metabolic costs of walking (C w) and running (C r) per unit distance (J kg-1 m-1). RESULTS: Oxygen uptake and metabolic power increased linearly with velocity. Between 0.3 and 0.7 ms-1, C w < C r. At 0.8 ms-1 there was no difference and extrapolation suggests that at faster velocities, running likely costs less than walking. CONCLUSION: On a 30° incline, metabolic power increases linearly with velocity. At speeds slower than 0.7 ms-1, walking requires less metabolic power than running (W kg-1) suggesting most VK racers should walk rather than run.

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