Ari T Nummela

KIHU - Research Institute for Olympic Sports

Purpose Very low intensity endurance training (LIT) does not seem to improve maximal oxygen uptake. The purpose of the present study was to investigate if very high volume of LIT could compensate the lack of intensity and is LIT affecting differently low and high intensity performances. Methods Recreationally active untrained participants (n = 35;...

Purpose : Without appropriate standardization of exercise doses, comparing high- (HI) and low-intensity (LI) training outcomes might become a matter of speculation. In athletic preparation, proper quantification ensures an optimized stress-to-recovery ratio. This review aims to compare HI and LI doses by estimating theoretically the conversion rati...

Study aim : Although exercise enjoyment is well studied in behavioral context, its associations to aerobic fitness adaptations during exercise interventions have received less attention. Material and methods : Untrained participants (n = 37, 21 females), cycled either at low intensity (LIT) (n = 18, mean training time 6.7 ± 0.7 h/week) or high inte...

Purpose To investigate whether 4 weeks of normobaric “live high–train low and high” (LHTLH) causes different hematological, cardiorespiratory, and sea‐level performance changes compared to living and training in normoxia during a preparation season. Methods Nineteen (13 women, 6 men) cross‐country skiers competing at the national or international...

Introduction: This is one of the first intervention studies to examine how low- (LIT) and high-intensity endurance training (HIT) affect durability, defined as ‘time of onset and magnitude of deterioration in physiological-profiling characteristics over time during prolonged exercise’. Methods: Sedentary and recreationally active men (n = 16) and w...

This study examined the predictive quality of intervals performed at maximal sustainable effort to predict 3-km and 10-km running times. In addition, changes in interval performance and associated changes in running performance were investigated. Either 6-week (10-km group, n = 29) or 2-week (3-km group, n = 16) interval training periods were perfo...

Purpose: Long-term development of endurance performance requires a proper balance between strain and recovery. While responses and adaptations to training are highly individual, this study examined whether individually-adjusted endurance training based on recovery and training status would lead to greater adaptations compared to a predefined progr...

Purpose: To assess the reliability of nocturnal heart rate (HR) and HR variability (HRV) and to analyze the sensitivity of these markers to maximal endurance exercise. Methods: Recreational runners recorded nocturnal HR and HRV on nights after 2 identical low-intensity training sessions (n = 15) and on nights before and after a 3000-m running te...

Purpose: This study examined the physiological, perceptual, and performance responses to a 2-week block of increased training load and compared whether responses differ between high-intensity interval (HIIT) and low-intensity (LIT) endurance training. Methods: Thirty recreationally trained males and females performed a two-week block of 10 HIIT-se...

Purpose The purpose of this study was to compare heart rate (HR) and heart rate variability in young endurance athletes during nocturnal sleep and in the morning; and to assess whether changes in these values are associated with changes in submaximal running (SRT) and counter-movement jump (CMJ) performance. Methods During a three-week period of s...

The aims of the current study were to examine the relationships between heart rate variability (HRV), salivary cortisol, sleep duration and training in young athletes. Eight athletes (16 ± 1 years) were monitored for 7 weeks during training and competition seasons. Subjects were training for endurance-based winter sports (cross-country skiing and b...

The purpose of the study was to examine the effects of progressively increased training intensity or volume on the nocturnal heart rate (HR) and heart rate variability (HRV), countermovement jump, perceived recovery, and heart rate-running speed index (HR-RS index). Another aim was to analyze how observed patterns during the training period in thes...

This study investigated acute responses and post 24-h recovery to four running sessions performed at different intensity zones by supine heart rate variability, countermovement jump, and a submaximal running test. A total of 24 recreationally endurance-trained male subjects performed 90 min low-intensity (LIT), 30 min moderate-intensity (MOD), 6×3...

The present study investigated if athletes can be classified as responders or non‐responders based on their individual change in total hemoglobin mass (tHb‐mass) following altitude training while also identifying the potential factors that may affect responsiveness to altitude exposure. Measurements were completed with 59 elite endurance athletes w...

BACKGROUND Heart rate (HR) and heart rate variability (HRV) measurements are widely used in the monitoring of stress and recovery status among sedentary people and athletes. However, effective HRV monitoring should be daily basis because sparse measurements do not bring forth the complete view about the stress and recovery balance. Morning electroc...

Background Heart rate (HR) and heart rate variability (HRV) measurements are widely used to monitor stress and recovery status in sedentary people and athletes. However, effective HRV monitoring should occur on a daily basis because sparse measurements do not allow for a complete view of the stress-recovery balance. Morning electrocardiography (ECG...

This study investigated maturation-related differences in neuromuscular fatigue after a short-term maximal run. Eight male children, eight adolescents, and eight adults performed a maximal ~50 s (300/350/400 m, respectively) run. Mechanisms of neuromuscular fatigue were assessed through isometric plantar flexor tests, electrical stimulation of the...

INTRODUCTION: Work economy is one key factor in endurance performance. In addition to technique, neuromuscular characteristics has been associated with work economy. Cross-country (XC) sprint skiers have been observed to be faster and stronger compared with distance-specialized (DIST) skiers (Hebert-Losier et al. 2016). The purpose of this study wa...

The return towards resting homeostasis in the post-exercise period has the potential to represent the internal training load of the preceding exercise bout. However, the relative potential of metabolic and autonomic recovery measurements in this role has not previously been established. Therefore the aim of this study was to investigate which of 4...

1.1 Objective: The purpose of this study was to investigate oxygen uptake, acid-base balance and energy system contributions during and after short maximal running in adult (n = 8), adolescent (n = 8) and child (n = 8) male athletes. 1.2 Methods: The tests included a maximal time trial of 400 m, 350 m and 300 m for different age groups respectively...

The aim of this study was to investigate whether a submaximal running test (SRT) with post-exercise heart rate recovery, heart rate variability and countermovement jump measurements could be used to monitor endurance training adaptation. Thirty-five endurance trained men and women completed an 18-week endurance training program. Maximal endurance p...

Unlabelled: Regular monitoring of adaptation to training is important for optimizing training load and recovery, which is the main factor in successful training. Purpose: To investigate the usefulness of a novel submaximal running test (SRT) in field conditions in predicting and tracking changes of endurance performance. Methods: Thirty-five e...

The effects of endurance training on endurance performance characteristics and cardiac autonomic modulation during night sleep were investigated during two 4-week training periods. After the first 4-week training period (3 x 40 min per week, at 75% of HRR) the subjects were divided into HIGH group (n = 7), who performed three high-intensity enduran...

Introduction: Measures of heart rate variability (HRV) have shown potential to be of use in training prescription. Purpose: The aim of this study was to investigate the effectiveness of using HRV in endurance training prescription. Methods: Forty recreational endurance runners were divided into the HRV-guided experimental training group (EXP)...

The aim of this study was to investigate the agreement in nocturnal and morning heart rate (HR) derived indices obtained the same day. Eighteen subjects performed all testing and measurements (10 men, age 36.4 ± 6.1 yr; height 178.3 ± 5.2 cm; weight 77.8 ± 6.2 kg; VO2max 55.7 ± 6.0 ml/kg/min; 8 women, age 34.1 ± 7.5 yr; height 166.8 ± 6.7 cm; weigh...

The aim of this study was to investigate factors that can predict individual adaptation to high-volume or high-intensity endurance training. After the first 8-week preparation period, 37 recreational endurance runners were matched into the high-volume training group (HVT) and high-intensity training group (HIT). During the next 8-week training peri...

Individual Adaptation to Endurance Training Guided by Heart Rate Variability HEIKURA, I.2, VESTERINEN, V.1, MERO, A.2 & NUMMELA, A.1 1Finnish Research Institute for Olympic Sports 2Department of Biology of Physical Activity, University of Jyväskylä Introduction. Heart rate variability (HRV) reflects the function of the autonomic nervous system....

Purpose: To examine acute responses of force production and oxygen uptake to combined strength (S) and endurance-running (E) loading sessions in which the order of exercises is reversed (ES vs SE). Methods: This crossover study design included recreationally endurance-trained men and women (age 21-45 y; n=12 men, 10 women) who performed ES and S...

Abstract The study examined the acute neuromuscular and metabolic responses and recovery (24 and 48 h) to combined strength and endurance sessions (SEs). Recreationally endurance trained men (n = 12) and women (n = 10) performed: endurance running followed immediately by a strength loading (combined endurance and strength session (ES)) and the reve...

The aim of this study was to investigate whether a novel heart rate-running speed index could be used in monitoring adaptation to endurance training. Forty-five recreational runners underwent a two-phased 28-week training regime. The first 14-weeks included basic endurance training whereas the second 14-weeks were more intensive (increased volume a...

In this study, changes in skiing performance and poling kinetics during a simulated cross-country sprint skiing competition were investigated. Twelve elite male cross-country skiers performed simulated sprint competition (4 x 1,150 m heat with 20 min recovery between the heats) using the double-poling technique. Vertical and horizontal pole forces...

Supervised periodized mixed maximal and explosive strength training added to endurance training in recreational endurance runners was examined over an 8-week intervention preceded by an 8-week preparatory strength training period. Thirty-four subjects (21-45 years) were divided into experimental groups: men (M, n = 9), women (W, 9) and control grou...

The aim of this study was to investigate whether nocturnal heart rate variability (HRV) can be used to predict changes in endurance performance during 28 weeks of endurance training. The training was divided into 14 weeks of basic training (BTP) and 14 weeks of intensive training periods (ITP). Endurance performance characteristics, nocturnal HRV,...

This study compared the effects of mixed maximal strength and explosive strength training with maximal strength training and explosive strength training combined with endurance training over an 8-week training intervention. Male subjects (age 21–45 years) were divided into three strength training groups, maximal (MAX, n = 11), explosive (EXP, 10) a...

The purpose of this study was to assess the effects of heavy resistance, explosive resistance, and muscle endurance training on neuromuscular, endurance, and high-intensity running performance in recreational endurance runners. Twenty-seven male runners were divided into one of three groups: heavy resistance, explosive resistance or muscle enduranc...

Heart rate (HR) as an estimator of oxygen consumption (VO(2) ) usually requires HR to be individually calibrated in a separate test. This study examined the validity of a new HR - and HR variability-based method (Firstbeat PRO heartbeat analysis software) in the estimation of VO(2) in real-life tasks. The method takes into account the respiration r...

Overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues, organs and/or body. However, there is no “golden standard” for TL measurement. The aim of the present study was to investigate if post-exercise heart rate variability (HRV) could be used to evaluate TL of interval running...

This study examined effects of periodized maximal versus explosive strength training and reduced strength training, combined with endurance training, on neuromuscular and endurance performance in recreational endurance runners. Subjects first completed 6 weeks of preparatory strength training. Then, groups of maximal strength (MAX, n=11), explosive...

This study examined the effects of endurance exercise on nocturnal autonomic modulation. Nocturnal R-R intervals were collected after a rest day, after a moderate endurance exercise and after a marathon run in ten healthy, physically active men. Heart rate variability (HRV) was analyzed as a continuous four-hour period starting 30 min after going t...

The effects of endurance training on endurance performance characteristics and cardiac autonomic modulation during night sleep were investigated. Twenty-four sedentary subjects trained over four weeks two hours per week at an average running intensity of 76+/-4% of their heart rate reserve. The R to R ECG-intervals were recorded and heart rate vari...

The present study investigated the performance-predicting factors of a simulated cross-country (XC) skiing sprint competition on roller skis, on a slow surface. Sixteen elite male XC skiers performed a simulated sprint competition (4 x 850 m heat with a 20-minute recovery) using V2 skating technique on an indoor tartan track. Heat velocities, oxyge...

The present chapter was designed to investigate the performance and fatigue in anincremental 6 × 1000 m running test. Well-trained endurance athletes performed eightnon-fatigued sprints from 5 m · s-1 to maximal velocity and the 6 x 1000 m running test ona 200-m indoor track. In order to investigate the fatigue induced changes in forceproduction du...

The overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues, organs, and/or body. However, there is no "golden standard" for TL measurement. The aim of this study was to examine if any post-exercise heart rate variability (HRV) indices could be used to evaluate TL in exercises w...

The aim of this study was to assess fatigue during a simulated cross-country skiing sprint competition based on skating technique. Sixteen male skiers performed a 30-m maximal skiing speed test and four 850-m heats with roller skies on a tartan track, separated by 20 min recovery between heats. Physiological variables (heart rate, blood lactate con...

This study investigated fatigue-induced changes in neuromuscular and stride characteristics during and immediately after the 5-km running time trial. Eighteen well-trained male distance runners performed a maximal 20-m sprint test and maximal voluntary contraction (MVC) in a leg press machine before and immediately after the 5-km running time trial...

Lifestyle related health problems are increasing rapidly. Many of them could be prevented or alleviated by sufficient physical activity, enough sleep, and a balanced diet. Individual citizens have the main responsibility for their own health and wellness management in their daily lives. Motivational tools based on modern technologies can support pe...

Since heart rate variability (HRV) during the first minutes of the recovery after exercise has barely been studied, we wanted to find out HRV dynamics immediately after five different constant-speed exercises. Thirteen sedentary women performed two low-intensity (3,500 m [3,500(LI)] and 7,000 m [7,000(LI)] at 50% of the velocity of VO(2max) [vVO(2m...

It is difficult to interpret the training induced changes in middle-distance running, since numerous aerobic and anaerobic determinants of the performance are interdependent. Several aerobic and anaerobic tests are available but their results, particularly those from anaerobic tests, may be discordant, not providing univocal interpretation of train...

The main purpose of the present study was to investigate the relationships between running mechanics, top running speed and economy in young endurance athletes. Twenty five endurance athletes (age 19.8 +/- 1.1 years, stature 1.82 +/- 0.07 m and body mass 69.4 +/- 7.5 kg) performed two separate tests on an indoor track. The first test was 8 x 30 m w...

To study effects of concurrent explosive strength and endurance training on aerobic and anaerobic performance and neuromuscular characteristics, 13 experimental (E) and 12 control (C) young (16 - 18 years) distance runners trained for eight weeks with the same total training volume but 19% of the endurance training in E was replaced by explosive tr...