Blaž Jereb | University of Ljubljana (original) (raw)
Papers by Blaž Jereb
ISBS - Conference Proceedings Archive, 1998
ISBS - Conference Proceedings Archive, 1994
International Journal of Environmental Research and Public Health, Aug 31, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
ISBS - Conference Proceedings Archive, 1996
Sustainability, Sep 2, 2022
European Journal of Sport Science, 2011
... Jensen, RL and Ebben, WP 2003. Kinetic analysis of complex training rest interval effect on v... more ... Jensen, RL and Ebben, WP 2003. Kinetic analysis of complex training rest interval effect on vertical jump performance. Journal of Strength and Conditioning Research , 17: 345–349. [PubMed], [Web of Science ®], [CSA] View all references). ...
International Journal of Environmental Research and Public Health
Neuromuscular fatigue after stretch-shortening cycle (SSC) exercise was analysed. Eleven healthy ... more Neuromuscular fatigue after stretch-shortening cycle (SSC) exercise was analysed. Eleven healthy sport students performed maximal hops for 60 secs on a force plate. After the workout, a statistically significant increase in the blood lactate concentration was found (before workout 0.73 mmol/l, three minutes after workout 6.41 mmol/l, (P<0.001)). During the hopping, maximal height was decreased for 3 cm (P<0.002). Contact times were shortened statistically significant, too (P<0.001). There were no statistically significantly changes in power or in fatigue index. Electrical stimulation of the vastus lateralis muscle resulted in a decreased twitch force (12%), contraction time and half relaxation timewere also shorter, but the changes were not statistically significant. Torque during 20 Hz stimulation showed a trend of increase. Torque during 100 Hz stimulation was significantly lower (P<0.001). Results showed that a high frequency fatigue was present after the hopping, not...
Neuromuscular fatigue during and after short maximally intensive concentric exercise was analyzed... more Neuromuscular fatigue during and after short maximally intensive concentric exercise was analyzed. Nine healthy sport students performed the 15s Wingate test. Maximal cycling power decreased by 1.86 W × kg-1 (p<0.001) during the cycling. After the exercise, a significant increase in the blood lactate concentration was found (1.13 mM × l-1) before the exercise and 6.7 mM × l-1 seven minutes after the exercise (p<0.05). Electrical stimulation of the vastus lateralis muscle resulted in a decreased twitch maximum force by 30 % (p<0.001). Contraction time and half relaxation timewere shorter, but not significantly (p<0.05). Torque at 20 Hz stimulation decreased by 20 % (p<0.003), while torque at 100 Hz stimulation was lowered by 10 % (p<0.000). The results after the 15s maximally intensive cycling pointed to high and low frequency fatigue, however, it seems that low frequency fatigue prevailed.Uvod U sportu je umor nepožeIjan. Da bismo ga kontroIiraIi, potreban nam je p...
European Journal of Applied Physiology, 2007
Ice-climbers frequently use the squeezing of rubber rings for increasing their isometric strength... more Ice-climbers frequently use the squeezing of rubber rings for increasing their isometric strength-endurance in the forearm muscles. The aim of this study was to ascertain whether such training influences oxygenation and endurance of forearm muscles at higher as well as lower testing intensities. Fourteen healthy young ice-climbers were divided and randomized into two groups. Group A performed a specific ice-climbing test, an ice-axe-grasping (axe weight 750 g) until fatigue. Group B performed 150 N isometric hand-squeezing of dynamometer until fatigue. Both groups performed similar training of squeezing a rubber ring at 30% of Maximal Voluntary Contraction (MVC) for 6 weeks. The forearm oxygenation was assessed by relative saturation of oxygen (RSO(2)), total hemoglobin concentration (RTOTHb), the concentration of oxygenated hemoglobin (ROXYHb) and concentration of deoxygenated hemoglobin (RDEOXYHb). The results revealed that muscle strength-endurance training increased performance of forearm muscles during 150 N contraction with an accompanied increase in oxygenation of the exercising muscles. In contrast, the same training did not influence the performance of forearm muscles during ice-axe-grasping in spite of increased oxygenation. Muscle oxygenation during intense isometric contraction is low in spite of an increase observed in training. This may be due to oxygenation levels that were below the limit where oxygenation may influence the duration of the contraction. Increased oxygenation may have occurred due to an increased blood flow and perfusion through superficial muscles or layers may not have contributed to the generation of the force of the contraction, as would be the case in deeper muscle layers.
Acta Universitatis Palackianae Olomucensis. Gymnica, 2007
Cílem našeho výzkumného projektu bylo zavést srdeč ní frekvenci jako jeden z možných indikátorů z... more Cílem našeho výzkumného projektu bylo zavést srdeč ní frekvenci jako jeden z možných indikátorů zátěže při sportovním lezení. Za účelem našeho výzkumu absolvovalo 11 sportovních horolezců tři trasy o různých stupních náročnosti. Byla měřena srdeční frekvence horolezců a počítána zátěž při lezení. Při analýze výsledků jsme sledovali, zda naměřené hodnoty skutečně odrážejí zvýšenou zátěž, nebo zda jsou znakem nějakého jiného jevu, který nebyl monitorován. Změny srdeční frekvence při sportovním lezení mohou nastat v důsledku různých faktorů, které nelze v úplnosti kon trolovat. Monitorování srdeční frekvence jako indikátoru zátěže při sportovním lezení se tedy jeví jako značně pochybné. The objective of our research project was to introduce heart rate during sport climbing as one of the possible indicators of climbing intensity. For the purpose of our research, 11 sport climbers climbed three routes of varying grades of difficulty. The heart rate of the climbers was measured and climbi...
Sport Mont Journal, 2010
The aim of the present study is to monitor heart rate (HR) at real and at simulated altitude befo... more The aim of the present study is to monitor heart rate (HR) at real and at simulated altitude before and immediately after acclimatization, and one month after acclimatization. Six students of Faculty of Sport in Ljubljana (two women and four men) participated in the study. They undergone 18-day long acclimatization process on 2100 - 5642 m. HR was measured during the step test at 300 m, 2100 m, and 3800 m (in a laboratory »Josef Stefan« Ljubljana, at simulated altitude). The results show that the HR decreased significant immediately after acclimatization comparing to the values before acclimatization. HR values returned to the values before acclimatization one month after acclimatization.
Sport Mont Journal, 2011
Climbing rope is certainly one of the most important pieces of climbing equipment. On market ther... more Climbing rope is certainly one of the most important pieces of climbing equipment. On market there are many manufacturers of dynamic climbing ropes and even more of their products. All the ropes meet the requirements of the standards, which ensure that the ropes are safe enough for use in climbing. However the requirements are set only under certain conditions. In reality climbing ropes are exposed to various conditions that are many times different to those set by the standards. Consequently there are many different falls, which lead to very different loads of impact. By using appropriate method of testing rope samples made by three different manufacturers we discovered that there are differences between all three manufacturers. This leads us to a suggestion that standards should be improved.
Sport Mont Journal, 2009
The objective of our research was to identify the impact of sport climbing on some morphologic ch... more The objective of our research was to identify the impact of sport climbing on some morphologic characteristics and motor abilities in climbers. The sample group consisted of 19 climbers, who trained climbing for one year beside their regular physical education after the initially survey was made, and 72 nonclimbers, who's only sport activity was their regular physical education. At the time of the test, climbers as well as nonclimbers were 14 years of age. The measurement included all the variables from the Physical education chart. Data were processed with statistical programme package SPSS for Windows. The result of analysis of covariance show that after a year long period of sport climbing statistically significant differences were shown in the results of t he test Polygon backwards in favour of the experimental group. It is also possible to observe a trend towards better results of the experimental group in the tests Skin fold thickness of the upper arm and Bend and touch on...
Sport Mont Journal, 2009
The purpose of our study was to establish the differences in some anthropometric measures and mot... more The purpose of our study was to establish the differences in some anthropometric measures and motor abilities between mountaineers and sport climbers. Our sample consisted of 11 top mountaineers and 12 members of A and B national teams in sport climbing. The survey was carried out by means of a standard battery of tests. Anthropo- metric measures were represented by 5 variables, while motor abilities were represented by 14 variables. Motor ability tests were divided into two groups due to a large number of variables. Mobility was surveyed with 6 tests and strength with 8 tests. The data we- re processed with statistical programme package SPSS with the method of discriminant analysis. Discriminant analysis was made separately of anthropometry, mobility and strength. Discriminant function statistically significantly divides mountaineers from sport climbers in anthropometric measures as well as mobility. In the field of strength, stati- stically significant differences between mountain...
The human body's adaptation to the decreased partial pressure of oxygen is called altitude ac... more The human body's adaptation to the decreased partial pressure of oxygen is called altitude acclimatisation. It is particularly important for alpinists who perform high-intensity workouts at a high altitude. Assessing someone's level of acclimatisation is a difficult problem. In our study, which was conducted prior to and during an expedition to the Peruvian Andes in South America organised by the Faculty of Sports of the University of Ljubljana, our main goal was to analyse the heart rate (HR) as an indicator for assessing the level of acclimatisation to high altitudes. The experiment consisted of five testing sessions, based on a simple step test, before and during the expedition. Eleven people took part in the experiment, eight of whom were female. The analysis yielded interesting results especially in the change of HR after a prolonged time at higher altitudes. Contrary to other studies, our research showed an increase in HR after the acclimatisation period. We concluded ...
Hiking and climbing in high mountains are becoming very popular during the last decade. High moun... more Hiking and climbing in high mountains are becoming very popular during the last decade. High mountain climbing is mainly in the domain of skilled alpinis ts. On the other hand hiking is often organized by trekking agencies which took unskilled clients to v ery high mountains. The aim of the presents study i s to emphasis the importance of the process of acclimati zation to high altitude. Two students of Faculty of sport in Ljubljana participated in the study: one w ith long end the second one with short acclimatizat ion time. The effects were monitored with heart rate me asurement in rest and during the step test. Measurements were conduct before and after the acclimatization, at two locations: high altitude simulation chamber in Ljubljana and real altitude i n Elbrus, Kavkaz, both at 2100 m. The results showed that heart rate decreased with longer acclimatizati on time. Heart rate at person A was lower for eight een beats per minute in rest and for sixteen beats per minute during t...
ISBS - Conference Proceedings Archive, 1998
ISBS - Conference Proceedings Archive, 1994
International Journal of Environmental Research and Public Health, Aug 31, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
ISBS - Conference Proceedings Archive, 1996
Sustainability, Sep 2, 2022
European Journal of Sport Science, 2011
... Jensen, RL and Ebben, WP 2003. Kinetic analysis of complex training rest interval effect on v... more ... Jensen, RL and Ebben, WP 2003. Kinetic analysis of complex training rest interval effect on vertical jump performance. Journal of Strength and Conditioning Research , 17: 345–349. [PubMed], [Web of Science ®], [CSA] View all references). ...
International Journal of Environmental Research and Public Health
Neuromuscular fatigue after stretch-shortening cycle (SSC) exercise was analysed. Eleven healthy ... more Neuromuscular fatigue after stretch-shortening cycle (SSC) exercise was analysed. Eleven healthy sport students performed maximal hops for 60 secs on a force plate. After the workout, a statistically significant increase in the blood lactate concentration was found (before workout 0.73 mmol/l, three minutes after workout 6.41 mmol/l, (P<0.001)). During the hopping, maximal height was decreased for 3 cm (P<0.002). Contact times were shortened statistically significant, too (P<0.001). There were no statistically significantly changes in power or in fatigue index. Electrical stimulation of the vastus lateralis muscle resulted in a decreased twitch force (12%), contraction time and half relaxation timewere also shorter, but the changes were not statistically significant. Torque during 20 Hz stimulation showed a trend of increase. Torque during 100 Hz stimulation was significantly lower (P<0.001). Results showed that a high frequency fatigue was present after the hopping, not...
Neuromuscular fatigue during and after short maximally intensive concentric exercise was analyzed... more Neuromuscular fatigue during and after short maximally intensive concentric exercise was analyzed. Nine healthy sport students performed the 15s Wingate test. Maximal cycling power decreased by 1.86 W × kg-1 (p<0.001) during the cycling. After the exercise, a significant increase in the blood lactate concentration was found (1.13 mM × l-1) before the exercise and 6.7 mM × l-1 seven minutes after the exercise (p<0.05). Electrical stimulation of the vastus lateralis muscle resulted in a decreased twitch maximum force by 30 % (p<0.001). Contraction time and half relaxation timewere shorter, but not significantly (p<0.05). Torque at 20 Hz stimulation decreased by 20 % (p<0.003), while torque at 100 Hz stimulation was lowered by 10 % (p<0.000). The results after the 15s maximally intensive cycling pointed to high and low frequency fatigue, however, it seems that low frequency fatigue prevailed.Uvod U sportu je umor nepožeIjan. Da bismo ga kontroIiraIi, potreban nam je p...
European Journal of Applied Physiology, 2007
Ice-climbers frequently use the squeezing of rubber rings for increasing their isometric strength... more Ice-climbers frequently use the squeezing of rubber rings for increasing their isometric strength-endurance in the forearm muscles. The aim of this study was to ascertain whether such training influences oxygenation and endurance of forearm muscles at higher as well as lower testing intensities. Fourteen healthy young ice-climbers were divided and randomized into two groups. Group A performed a specific ice-climbing test, an ice-axe-grasping (axe weight 750 g) until fatigue. Group B performed 150 N isometric hand-squeezing of dynamometer until fatigue. Both groups performed similar training of squeezing a rubber ring at 30% of Maximal Voluntary Contraction (MVC) for 6 weeks. The forearm oxygenation was assessed by relative saturation of oxygen (RSO(2)), total hemoglobin concentration (RTOTHb), the concentration of oxygenated hemoglobin (ROXYHb) and concentration of deoxygenated hemoglobin (RDEOXYHb). The results revealed that muscle strength-endurance training increased performance of forearm muscles during 150 N contraction with an accompanied increase in oxygenation of the exercising muscles. In contrast, the same training did not influence the performance of forearm muscles during ice-axe-grasping in spite of increased oxygenation. Muscle oxygenation during intense isometric contraction is low in spite of an increase observed in training. This may be due to oxygenation levels that were below the limit where oxygenation may influence the duration of the contraction. Increased oxygenation may have occurred due to an increased blood flow and perfusion through superficial muscles or layers may not have contributed to the generation of the force of the contraction, as would be the case in deeper muscle layers.
Acta Universitatis Palackianae Olomucensis. Gymnica, 2007
Cílem našeho výzkumného projektu bylo zavést srdeč ní frekvenci jako jeden z možných indikátorů z... more Cílem našeho výzkumného projektu bylo zavést srdeč ní frekvenci jako jeden z možných indikátorů zátěže při sportovním lezení. Za účelem našeho výzkumu absolvovalo 11 sportovních horolezců tři trasy o různých stupních náročnosti. Byla měřena srdeční frekvence horolezců a počítána zátěž při lezení. Při analýze výsledků jsme sledovali, zda naměřené hodnoty skutečně odrážejí zvýšenou zátěž, nebo zda jsou znakem nějakého jiného jevu, který nebyl monitorován. Změny srdeční frekvence při sportovním lezení mohou nastat v důsledku různých faktorů, které nelze v úplnosti kon trolovat. Monitorování srdeční frekvence jako indikátoru zátěže při sportovním lezení se tedy jeví jako značně pochybné. The objective of our research project was to introduce heart rate during sport climbing as one of the possible indicators of climbing intensity. For the purpose of our research, 11 sport climbers climbed three routes of varying grades of difficulty. The heart rate of the climbers was measured and climbi...
Sport Mont Journal, 2010
The aim of the present study is to monitor heart rate (HR) at real and at simulated altitude befo... more The aim of the present study is to monitor heart rate (HR) at real and at simulated altitude before and immediately after acclimatization, and one month after acclimatization. Six students of Faculty of Sport in Ljubljana (two women and four men) participated in the study. They undergone 18-day long acclimatization process on 2100 - 5642 m. HR was measured during the step test at 300 m, 2100 m, and 3800 m (in a laboratory »Josef Stefan« Ljubljana, at simulated altitude). The results show that the HR decreased significant immediately after acclimatization comparing to the values before acclimatization. HR values returned to the values before acclimatization one month after acclimatization.
Sport Mont Journal, 2011
Climbing rope is certainly one of the most important pieces of climbing equipment. On market ther... more Climbing rope is certainly one of the most important pieces of climbing equipment. On market there are many manufacturers of dynamic climbing ropes and even more of their products. All the ropes meet the requirements of the standards, which ensure that the ropes are safe enough for use in climbing. However the requirements are set only under certain conditions. In reality climbing ropes are exposed to various conditions that are many times different to those set by the standards. Consequently there are many different falls, which lead to very different loads of impact. By using appropriate method of testing rope samples made by three different manufacturers we discovered that there are differences between all three manufacturers. This leads us to a suggestion that standards should be improved.
Sport Mont Journal, 2009
The objective of our research was to identify the impact of sport climbing on some morphologic ch... more The objective of our research was to identify the impact of sport climbing on some morphologic characteristics and motor abilities in climbers. The sample group consisted of 19 climbers, who trained climbing for one year beside their regular physical education after the initially survey was made, and 72 nonclimbers, who's only sport activity was their regular physical education. At the time of the test, climbers as well as nonclimbers were 14 years of age. The measurement included all the variables from the Physical education chart. Data were processed with statistical programme package SPSS for Windows. The result of analysis of covariance show that after a year long period of sport climbing statistically significant differences were shown in the results of t he test Polygon backwards in favour of the experimental group. It is also possible to observe a trend towards better results of the experimental group in the tests Skin fold thickness of the upper arm and Bend and touch on...
Sport Mont Journal, 2009
The purpose of our study was to establish the differences in some anthropometric measures and mot... more The purpose of our study was to establish the differences in some anthropometric measures and motor abilities between mountaineers and sport climbers. Our sample consisted of 11 top mountaineers and 12 members of A and B national teams in sport climbing. The survey was carried out by means of a standard battery of tests. Anthropo- metric measures were represented by 5 variables, while motor abilities were represented by 14 variables. Motor ability tests were divided into two groups due to a large number of variables. Mobility was surveyed with 6 tests and strength with 8 tests. The data we- re processed with statistical programme package SPSS with the method of discriminant analysis. Discriminant analysis was made separately of anthropometry, mobility and strength. Discriminant function statistically significantly divides mountaineers from sport climbers in anthropometric measures as well as mobility. In the field of strength, stati- stically significant differences between mountain...
The human body's adaptation to the decreased partial pressure of oxygen is called altitude ac... more The human body's adaptation to the decreased partial pressure of oxygen is called altitude acclimatisation. It is particularly important for alpinists who perform high-intensity workouts at a high altitude. Assessing someone's level of acclimatisation is a difficult problem. In our study, which was conducted prior to and during an expedition to the Peruvian Andes in South America organised by the Faculty of Sports of the University of Ljubljana, our main goal was to analyse the heart rate (HR) as an indicator for assessing the level of acclimatisation to high altitudes. The experiment consisted of five testing sessions, based on a simple step test, before and during the expedition. Eleven people took part in the experiment, eight of whom were female. The analysis yielded interesting results especially in the change of HR after a prolonged time at higher altitudes. Contrary to other studies, our research showed an increase in HR after the acclimatisation period. We concluded ...
Hiking and climbing in high mountains are becoming very popular during the last decade. High moun... more Hiking and climbing in high mountains are becoming very popular during the last decade. High mountain climbing is mainly in the domain of skilled alpinis ts. On the other hand hiking is often organized by trekking agencies which took unskilled clients to v ery high mountains. The aim of the presents study i s to emphasis the importance of the process of acclimati zation to high altitude. Two students of Faculty of sport in Ljubljana participated in the study: one w ith long end the second one with short acclimatizat ion time. The effects were monitored with heart rate me asurement in rest and during the step test. Measurements were conduct before and after the acclimatization, at two locations: high altitude simulation chamber in Ljubljana and real altitude i n Elbrus, Kavkaz, both at 2100 m. The results showed that heart rate decreased with longer acclimatizati on time. Heart rate at person A was lower for eight een beats per minute in rest and for sixteen beats per minute during t...