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Bente R. Jensen, Line Hovgaard-Hansen and Katrine L. Cappelen

Running on a lower-body positive-pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100%, 80%, 60%, 40%, and 20% body weight (BW). Surface electromyography, ground reaction force, and running characteristics were measured. Relative knee and ankle joint forces were estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and antigravity forces. At 20% BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100% BW values. Plantar flexors decreased to 52% and 58% at 20% BW, while activity of biceps femoris muscle remained unchanged. Unweighting with LBPP reduced estimated joint force significantly although less than proportional to the degree of weight support (ankle).It was concluded that leg muscle activation adapted to the new biomechanical environment, and the effect of unweighting on estimated knee force was more pronounced than on ankle force.

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Ricardo J.S. Costa, Beat Knechtle, Mark Tarnopolsky and Martin D. Hoffman

Ultramarathon running events and participation numbers have increased progressively over the past three decades ( Deutsche Ultramarathon Vereinigung, 2018 ). Anecdotally, there has been growing interest from both amateur and elite endurance runners looking for new adventurous courses and challenges

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Douglas J. Casa, Samuel N. Cheuvront, Stuart D. Galloway and Susan M. Shirreffs

jump, long jump, triple jump, and pole vault) Mod Low High High Low Low b Low Low Throwing (shot put, javelin, and discus) Mod Low High High Low Low Low Low Sprints (<800 m) Mod Low High High Low Low Low Low Middle-distance running (800 m to 10 km) High Low Mod Low Mod Low Mod High Long

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Rahel Gilgen-Ammann, Wolfgang Taube and Thomas Wyss

Purpose:

To quantify gait asymmetry in well-trained runners with and without previous injuries during interval training sessions incorporating different distances.

Methods:

Twelve well-trained runners participated in 8 high-intensity interval-training sessions on a synthetic track over a 4-wk period. The training consisted of 10 × 400, 8 × 600, 7 × 800, and 6 × 1000-m running. Using an inertial measurement unit, the ground-contact time (GCT) of every step was recorded. To determine gait asymmetry, the GCTs between the left and right foot were compared.

Results:

Overall, gait asymmetry was 3.3% ± 1.4%, and over the course of a training session, the gait asymmetry did not change (F 1,33 = 1.673, P = .205). The gait asymmetry of the athletes with a previous history of injury was significantly greater than that of the athletes without a previous injury. However, this injury-related enlarged asymmetry was detectable only at short (400 m), but not at longer, distances (600–1000 m).

Conclusion:

The gait asymmetry of well-trained athletes differed, depending on their history of injury and the running distance. To detect gait asymmetries, high-intensity runs over relatively short distances are recommended.

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Hyunjae Jeon and Abbey C. Thomas

nontraumatic and nonabnormal structural pathology which is localized in the retropatellar region. 5 PFP accounts for up to 17% of visits to general practice physicians for knee pain. 6 In recreational athletes, the prevalence may be closer to 25%, with individuals participating in running- and jumping

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Avish P. Sharma, Philo U. Saunders, Laura A. Garvican-Lewis, Brad Clark, Jamie Stanley, Eileen Y. Robertson and Kevin G. Thompson

Purpose:

To determine the effect of training at 2100-m natural altitude on running speed (RS) during training sessions over a range of intensities relevant to middle-distance running performance.

Methods:

In an observational study, 19 elite middle-distance runners (mean ± SD age 25 ± 5 y, VO2max, 71 ± 5 mL · kg–1 · min–1) completed either 4–6 wk of sea-level training (CON, n = 7) or a 4- to 5-wk natural altitude-training camp living at 2100 m and training at 1400–2700 m (ALT, n = 12) after a period of sea-level training. Each training session was recorded on a GPS watch, and athletes also provided a score for session rating of perceived exertion (sRPE). Training sessions were grouped according to duration and intensity. RS (km/h) and sRPE from matched training sessions completed at sea level and 2100 m were compared within ALT, with sessions completed at sea level in CON describing normal variation.

Results:

In ALT, RS was reduced at altitude compared with sea level, with the greatest decrements observed during threshold- and VO2max-intensity sessions (5.8% and 3.6%, respectively). Velocity of low-intensity and race-pace sessions completed at a lower altitude (1400 m) and/or with additional recovery was maintained in ALT, though at a significantly greater sRPE (P = .04 and .05, respectively). There was no change in velocity or sRPE at any intensity in CON.

Conclusion:

RS in elite middle-distance athletes is adversely affected at 2100-m natural altitude, with levels of impairment dependent on the intensity of training. Maintenance of RS at certain intensities while training at altitude can result in a higher perceived exertion.

Open access

Øyvind Skattebo, Thomas Losnegard and Hans Kristian Stadheim

runners but compensate with a lower O 2 cost of running to achieve superior performance in long events. 1 Similarly, road cyclists who are uphill, flat, or time-trial specialists generally display anthropometrics and indexed VO 2 max values that are favorable for performance on either uphill or flat

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Chelsey Klimek, Christopher Ashbeck, Alexander J. Brook and Chris Durall

Search Strategy Term Used to Guide Search Strategy • P atient/Client group: CrossFit participants • I ntervention/Assessment: CrossFit • C omparison: running OR weightlifting OR exercise • O utcome(s): injury OR damage OR trauma OR incidence Sources of Evidence Searched • PubMed

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Patti Finke, Janet Hamilton, Warren Finke and Mike Broderick

The RRCA Coaching Certification program is a model for national coaching education. The goal of the RRCA coaching certification is to provide trained individuals to work as coaching professionals for the sport of distance running at all levels from beginner to advanced runners. A coaching program for distance running attracts more individuals to the sport, and more importantly, helps individuals train intelligently, extend their running careers, have more fun running, and minimize the risks of overuse injuries. The program has certified over 1600 coaches across the US.

Open access

Louise M. Burke, Asker E. Jeukendrup, Andrew M. Jones and Martin Mooses

The International Association of Athletics Federations recognizes various distance events, with current World Championship and Olympic Games hosting the 10,000-m track event and road marathon (42.2 km) in running and 20 and 50-km events in race walking. In addition, there are separate International