Rodríguez-Marroyo1, J.A. et al.: PHYSIOLOGICAL DEMANDS OF MOUNTAIN... Kinesiology 50(2018) Suppl.1:60-66 PHYSIOLOGICAL DEMANDS OF MOUNTAIN RUNNING RACES Jose A. Rodríguez-Marroyo1, Javier González-Lázaro2,3, Higinio F. Arribas-Cubero3,4, and José G. Villa1 1Department of Physical Education and Sports, Institute of Biomedicine (IBIOMED), University of León, León, Spain 2European University Miguel de Cervantes, Valladolid, Spain 3Castilla y León Mountain Sports, Climbing and Hiking Federation, Valladolid, Spain 4Faculty of Education and Social Work, University of Valladolid, Valladolid, Spain Original scientific paper UDC: 796.61.093.55:612.766.1 Abstract: The aim of this study was to analyze the exercise intensity and competition load (PL) based on heart rate (HR) during different mountain running races. Seven mountain runners participated in this study. They competed in vertical (VR), 10-25 km, 25-45 km and >45 km races. The HR response was measured during the races to calculate the exercise intensity and PL according to the HR at which both the ventilatory (VT) and respiratory compensation threshold (RCT) occurred. The exercise intensity below VT and between VT and RCT increased with mountain running race distance. Likewise, the percentage of racing time spent above RCT decreased when race duration increased. However, the time spent above RCT was similar between races (~50 min). The PL was significantly higher (p<.05) during the longest races (145.0±18.4, 288.8±72.5, 467.3±109.9 and 820.8±147.0 AU in VR, 10-25 km, 25-45 km and >45 km, respectively). The ratio of PL to accumulative altitude gain was similar in all races (~0.16 AU·m-1). In conclusion, outcomes from this study demonstrate the high exercise intensities and physiologic loads sustained by runners during different mountain races. Key words: heart rate, exercise intensity, competition load, endurance Introduction al., 2001; Ramos-Campo, et al., 2016; Saugy, et al., Participation in mountain running races has 2013; Vernillo, et al., 2015; Wüthrich, et al., 2015). experienced a significant increase in recent years Collectively, these works have shown a significant (Hoffman, Ong, & Wang, 2010). This fact has moti- impact on athletes participating in mountain ultra- vated the interest of the scientific community for the marathons: fatigue, muscular damage, negative en- ergy balance, and a high sympathetic modulation. study of these events (Clemente-Suárez, 2015; Ehr- However, a smaller number of studies have been ström, et al., 2017; Fornasiero, et al., 2017; Martin- performed on shorter duration races (Ehrström et ez, et al., 2018; Ramos-Campo, et al., 2016; Saugy, al., 2017; Giovanelli, et al., 2016). These have fo- et al., 2013; Vernillo, et al., 2015; Wüthrich, et al., cused on examining the metabolic cost of walking 2015). These races consist of running or walking or running across a wide range of slopes encoun- on mountain trails with positive and negative slopes tered in vertical kilometer races (i.e., 1,000 m ver- over different distances. Participants can reach an tical climb and ~5 km) (Giovanelli, et al., 2016) and accumulative altitude gain of ~24,000 m during the analyzing the physiological variables that contribute most extreme events (Saugy, et al., 2013). The In- to performance during short mountain races (Ehr- ternational Skyrunner Federation (http://www.sky- ström, et al., 2017). running.com/rules/) classifies mountain running Exercise intensity analysis can provide useful races according to their distance (from ~5 to 50-99 information on which to base conditioning pro- km) and elevation gain (from 1,000 to more than grams (Rodríguez-Marroyo, et al., 2011, 2012). Data 3,200 m vertical climb). Despite a wide variety of derived from the competition demands analysis can disciplines, most research has focused on studying be used as reference to adapt training programs and the most challenging events (i.e., mountain ultra- help coaches to develop more specific and scientifi- marathons) (Clemente-Suárez, et al., 2015; Fornasi- cally-based training programs. This type of analy- ero, et al., 2017; Martinez, et al., 2018; Neumayr, et sis has mostly been performed on endurance events 60 Rodríguez-Marroyo1, J.A. et al.: PHYSIOLOGICAL DEMANDS OF MOUNTAIN... Kinesiology 50(2018) Suppl.1:60-66 (Lucía, Hoyos, Carvajal, & Chicharro, 1999; Rod- (RCT) occurred. Consequently, the exercise inten- ríguez-Marroyo, et al., 2003, 2011; Rodríguez-Mar- sity during mountain running races, based on HR royo, García-López, Juneau, & Villa, 2009). How- was analyzed (Lucía, et al., 1999; Rodríguez-Mar- ever, to date there is a paucity of research that ana- royo, et al., 2003, 2009). lyze the physiological demands of mountain run- ning races (Clemente-Suárez, 2015; Fornasiero, et Graded exercise test al., 2017; Ramos-Campo, et al., 2016). To the best Laboratory environmental conditions (22ºC and of our knowledge, these studies have only focused 30% relative humidity) were standardized for all on analyzing the exercise intensity distribution and subjects. All tests were preceded by a 10-minute estimating energetic demand during mountain ul- warm-up period of running at 9-12 km·h-1 and free tramarathon races. Thus, using different intensity stretching for five minutes. The runners were en- zones established according to the heart rate (HR) couraged to have a light training session the day be- reserve (Clemente-Suárez, 2015; Ramos-Campo, fore and to follow a carbohydrate-rich diet. The test et al., 2016), or HR at the ventilatory thresholds was performed on a treadmill (h/p/cosmos pulsar, (Fornasiero, et al., 2017) the exercise intensity sus- h/p/cosmos sports & medical GMBH, Nussdorf- tained by mountain runners has been analyzed Traunstein, Germany) with a 1% gradient (Jones during 54 and 65 km events. Overall, these works & Doust, 1996). The initial speed was 6 km·h-1 and have shown high relative time spend in low inten- was increased by 1 km·h-1 every minute until voli- sity zones, i.e., below the ventilatory threshold or tional exhaustion. The maximal speed was deter- <70 % of HR reserve. However, it has been noted mined as the highest speed maintained for a com- that exercise duration affects athletes’ effort, which plete stage plus the interpolated speed from incom- can alter the exercise intensity distribution (Rod- plete stages (Kuipers, Verstappen, Keizer, Geurten, ríguez-Marroyo, et al., 2012). In this way a decrease & van Kranenburg, 1985). The HR response was in the race time might contribute to sustaining a measured telemetrically every five seconds (Polar higher exercise intensity (Rodríguez-Marroyo, et Vantage NV, Polar Electro Oy, Kempele, Finland) al., 2012). Therefore, the aim of this study was to and respiratory gas exchange was continuously analyze exercise intensity and competition load ex- measured breath-by-breath (Medisoft Ergocard, perienced by mountain runners during mountain Medisoft Group, Sorinnes, Belgium). The VO2max running races of different duration. The secondary and maximal HR were recorded as the highest val- aim of the study was to estimate energy expendi- ues obtained for the last 30-second period before ture during the races. exhaustion. The ventilatory (VT) and respiratory compensation (RCT) thresholds were identified ac- Methods cording to the following criteria (Davis, 1985): in- -1 crease in both VE·VO2 and PETO2 with no con- Participants -1 comitant increase in VE·VCO2 for VT, and an in- -1 -1 Seven male mountain runners (mean±SD, age crease in both VE·VO2 and VE·VCO 2 and a de- 33±6 years, body mass 74.4±7.1 kg, height 177.6±6.2 crease in PETCO2 for RCT. cm) participated in the study. Four subjects were of high competitive level; they usually finished Mountain running races among the top-20 positions in national events. During the competition period (April-August), They were classified as well-trained runners (65-71 the HR was recorded using the runners’ GPS ml·kg-1·min-1) (De Pauw, et al., 2013). All the sub- (Garmin Foreruner 405, Garmin International Inc., jects were experienced mountain race runners (7±2 Olathe, USA; Suunto Ambit2 S, Suunto Oy, Van- years) and had more than 10 years of training ex- taa, Finland) in different mountain running races in perience. They habitually trained 6.2±1.9 times order to analyze exercise intensity and physiologi- per week (10-20 weekly training hours) and usu- cal load (PL). Subsequently, using an open-source ally competed once every two weeks during the software (GoldenCheetah, v3.3.0), the data were competition period. Written informed consent was analyzed according to the cumulative time the run- obtained from all subjects. The protocol was ap- ners spent in different effort zones. Three intensity proved by the Ethics Committee of the University zones were established according to the reference of León, Spain, and conformed to the principles HR values corresponding to VT and RCT (Lucía, identified in the Declaration of Helsinki. et al., 1999; Rodríguez-Marroyo, et al., 2003, 2009, 2011): zone 1, below the VT (low intensity zone); Procedures zone 2, between VT and RCT (moderate intensity The study was carried out over one season. The zone); and zone 3, above RCT (high intensity zone). subjects performed a graded exercise test during These zones were used to determine the PL by mul- the precompetition period (February) to determine tiplying the time spent in zone 1, 2 and 3 by the their VO2max and the HR at which both their ventila- constants 1, 2 and 3, respectively. The total score tory (VT) and respiratory compensation threshold was obtained by summating the results of the three 61 Rodríguez-Marroyo1, J.A. et al.: PHYSIOLOGICAL DEMANDS OF MOUNTAIN... Kinesiology 50(2018) Suppl.1:60-66 zones (Foster, et al., 2001). Finally, energy expendi- altitude change increased with the length of the ture during the mountain running races was esti- races.