Abstract
purpose of this non-randomized study was to determine the effect of strength training and aerobic interval training on the anaerobic and aerobic power and endurance of young men (assessed by determination of the second ventilatory threshold (VT2)) in non-trained men. Participants (n = 45) were recruited into three groups of 15 each. The first group performed strength training (ST), the second performed aerobic interval training (AIT), and the third group was the control group (CON). In each group, somatic measurements and tests of aerobic (graded test with VT2 determination) and anaerobic capacity (Wingate test) were performed twice (before and after the exercise intervention in the training groups). In the graded test, the level of maximal load (Pmax), maximal oxygen uptake (VO2max) and intensity and oxygen uptake at VT2 were determined. In the Wingate test, peak power (PP) and mean power (MP) were determined. The exercise intervention in the ST and AIT groups lasted 6 weeks, with three workouts per week. Training in the ST and AIT groups resulted in significant increase in absolute Pmax (p< 0.001, ES = 0.52 andp< 0.05,ES = 0.36), VO2max (p< 0.001, ES = 0.50 andp= 0.02, ES = 0.55) in the participants. Only AIT was significantly effective in improving oxygen uptake at VT2 (p< 0.04, ES = 0.64), and ST in improving PP. Strength training can be an effective
and AIT groups resulted in significant increase in absolute Pmax (p< 0.001, ES = 0.52 andp< 0.05,ES = 0.36), VO2max (p< 0.001, ES = 0.50 andp= 0.02, ES = 0.55) in the participants. Only AIT was significantly effective in improving oxygen uptake at VT2 (p< 0.04, ES = 0.64), and ST in improving PP. Strength training can be an effective training method in training aerobic and anaerobic capacity (significantly increases Pmax, VO2max, and PP), while it does not significantly affect work intensity at VT2. Our results suggest that, particularly in anaerobic–aerobic sports, strength training may be a training method that can simultaneously improve both anaerobic power and maximal oxygen uptake. It can also complement endurance training. Keywords:strength; anaerobic; aerobic; power; endurance; training; intervals 1. Introduction High-intensity strength training (ST) has traditionally been used to improve anaerobic (phosphagen and glycolytic) capacity and to improve muscle strength, speed and power, as well as to improve tolerance of acid–base disturbances [1,2]. Strength training based on anaerobic exercises performed with external resistance is a kind of training that affects the nervous and muscular systems, among other things, by increasing the activation of motor units [3,4] or increasing the physiological cross-section of muscle fibers [5]. Strength training is gaining increasing interest in sports to improve aerobic capacity. Previous studies [6–8] have shown that ST (>70% of one repetition maximum (1RM) intensity) training increases not only maximal strength and peak power, but can increase maximal oxygen uptake (VO2max) and improve cyclists’ running economy [9]. In other studies, Appl. Sci.2025,15, 7953 https://doi.org/10.3390/app15147953
Appl. Sci.2025,15, 7953 2 of 16 improvements in endurance, as assessed by running economy, were observed after resis- tancetraining [10–13] . Another study [7] showed that strength training using free weights improved both aerobic and anaerobic capacity in female soccer players. Lower lactate con- centration was also observed after such training in comparison to aerobic training [8]. It has also been proven that 20-week ST has the effect of increasing blood indices, such as mean red blood cell volume, hematocrit and red blood cell count [14]. The authors [14] suggest that resistance training affects fluctuations in blood morphology parameters, causing an increase in red blood cell-related indices. It may counteract sports anemia, which often occurs among people who perform endurance training. Another study [15] showed that ST significantly improves, in a similar way to long-term aerobic training, cardiovascular function in obese individuals; after training, there was not only a significant increase in VO2max, but also improved endothelial function in blood vessels, an increase in PGC-1α, a protein responsible for regulating liver function during gluconeogenesis or mitochondrial biogenesis, and increased transport of calcium ions involved in muscle contraction. In addi- tion, a decrease in LDL lipoprotein levels was noted in the subjects [15]. The above-reported changes occurring under the influence of strength training may also have a beneficial effect on aerobic capacity and suggest that strength training may also be at least a complement or alternative to endurance training. One of the physiological indicators of aerobic endurance is VO2max, the intensity of work at metabolic thresholds (first and second ventilatory threshold: VT1 and VT2), maximal steady state and economy of movement [16–18]. As intensity increases to maximal, energy metabolism changes. Once the first ventilatory threshold is exceeded, compensated metabolic acidosis occurs [19]. Increasing exercise intensity causes the next metabolic threshold to be exceeded, which is the second ventilatory threshold (VT2), an important indicator in assessing aerobic endurance [20,21]. Exceeding VT2 causes hyperventilation and the development of uncompensated metabolic acidosis [22]. Aerobic capacity is usually trained using submaximal, continuous or interval aerobic efforts, usually performed over an extended period of time. The
[19]. Increasing exercise intensity causes the next metabolic threshold to be exceeded, which is the second ventilatory threshold (VT2), an important indicator in assessing aerobic endurance [20,21]. Exceeding VT2 causes hyperventilation and the development of uncompensated metabolic acidosis [22]. Aerobic capacity is usually trained using submaximal, continuous or interval aerobic efforts, usually performed over an extended period of time. The changes observed under the influence of endurance training mainly concern the functioning of the circulatory and respiratory systems and blood pa- rameters, which result in improved oxygen transport to cells. Therefore, if similar changes (i.e., an increase in the number of erythrocytes) were observed after strength training [14], this may suggest that strength training may also have an impact on aerobic performance. Most sports have a mixed energy background (aerobic–anaerobic or anaerobic– anaerobic), and thus, most often require two distinct training methods: one aimed at improving aerobic capacity, the other at improving anaerobic capacity. For practitioners, it is important to optimize training methods in order to maximize training effects. They seek either new training methods or combinations of several different methods to ensure maximum training effectiveness, especially when there is a short preparation period for a competition or a set goal. Previous studies [6–8] suggest that ST can also improve aerobic endurance and thus may prove to be a versatile training method, affecting both aerobic and anaerobic capacity. In this study, we compared the effectiveness in improving physical performance of two distinct training methods, aerobic and anaerobic, i.e., methods that produce different physiological and biochemical effects. The first, strength training, tar- geted improvements in muscle strength and anaerobic capacity. The second, AIT, targeted improving aerobic capacity. The purpose of the study was to determine the effectiveness of strength training in training aerobic endurance in young men, as assessed by maximal power, maximal oxygen uptake and second ventilatory threshold. It was hypothesized that strength training would be as effective in improving endurance capacity as traditional aerobic interval training.
training aerobic endurance in young men, as assessed by maximal power, maximal oxygen uptake and second ventilatory threshold. It was hypothesized that strength training would be as effective in improving endurance capacity as traditional aerobic interval training.
Appl. Sci.2025,15, 7953 3 of 16 2. Materials and Methods The study involved 45 young men, who were recruited into three groups of 15 partic- ipants each. The first group performed strength training, the second performed aerobic interval training, and the third group was without intervention (control—CON). In each group, somatic measurements, the Wingate test and aerobic capacity test were performed twice (before and after the exercise intervention). The preliminary tests were conducted prior to the intervention, followed by 6 weeks of intervention and a post-test within 1 week of the last training session. In addition, declared physical activity was determined in each participant. The exercise intervention in the ST and AIT groups lasted for 6 weeks, with three workouts per week. The CON group was without intervention for this period. Partic- ipants were instructed not to change their diet or physical activity during the intervention. Prior to the intervention, participants were familiarized with exercise testing procedures. One familiarization session was held, during which participants learned about the tech- nique of cycling on an ergometer (AIT) or the technique of performing specific strength exercises (ST); they had the opportunity to try out the exercises planned for the first week of the intervention. The safety rules for performing the exercises were also explained to them. At the end of each week of the intervention (ST), the instructor presented new exercises to be introduced the following week. On the first day of the study, participants took somatic measurements and then performed a graded test to assess aerobic capacity. The next day they performed the Wingate test. Participants had to refrain from eating for 2 h before the exercise tests and were asked not to participate in any intense exercise for 24 h before the exercise tests and to hydrate during this time. They were not allowed to consume alcohol or caffeinated beverages before the performance tests. All tests were conducted at the same time of day starting at 8 a.m., after the participants had consumed a light meal. The workouts took place under the supervision of a sports/motor training instructor. Exercise tests
before the exercise tests and to hydrate during this time. They were not allowed to consume alcohol or caffeinated beverages before the performance tests. All tests were conducted at the same time of day starting at 8 a.m., after the participants had consumed a light meal. The workouts took place under the supervision of a sports/motor training instructor. Exercise tests and workouts took place under similar conditions, with an ambient temperature of about 21 ◦ C and humidity of about 40%. This study was not randomized. For organizational reasons, the study was conducted in stages, i.e., group by group. After completing the measurements/interventions in one group, participants were recruited for the next group. A total of 68 men were recruited for the study, 3 of whom were excluded due to failure to meet the inclusion criteria. Young healthy men, declaring good health and without contraindications to high-intensity exercise, were recruited for the study. The following inclusion criteria were adopted: age (19–27 years), declared good general health (no chronic diseases, inflammation, history of fractures, surgery in the 6 months before the start of the project), no training in the 6 months before the start of the project. Exclusion criteria were regular physical activity (sports training), obesity or overweight, history of chronic conditions, injuries, cardiac contraindications to exercise. All participants gave written consent to participate in the study and were informed about the purpose of the study and the scope of the study. Approval for the study was obtained from the Bioethics Committee of the Regional Medical Chamber in Kraków (187/KBL/OIL/2022). 2.1. Participants The study recruited young healthy men aged 19 to 27 years who did not participate in sports and their declared spontaneous, varied physical activity at a low to moderate intensity. The average age and somatic build of participants before the intervention are shown in Table.
Appl. Sci.2025,15, 7953 4 of 16 Table 1.Age and body build of the participants (data are presented as mean±SD). Variable Group Mean ±SD Age [yrs] CON 22.8 ±1.7 ST 22.4 ±3.2 AIT 20.6 ±1 BH [cm] CON 178.1 ±7.1 ST 179.7 ±4.3 AIT 180 ±5.7 BM [kg] CON 73.3 ±9.2 ST 82.9 ±8.3 AIT 77 ±8.6 LBM [kg] CON 60.2 ±6.4 ST 66 ±6.8 AIT 63.4 ±6.1 FM [kg] CON 13.1 ±4.3 ST 16.9 ±4.5 AIT 13.6 ±4.1 FM [%] CON 17.6 ±4.3 ST 20.3 ±4.5 AIT 17.4 ±3.9 BMI [kg/m 2 ] CON 23.1 ±2.1 ST 25.6 ±2.1 AIT 23.7 ±2.2 BH: body height; BM: body mass; LBM: lean body mass; FM: fat mass; BMI: body mass index; CON: control group; ST: strength training; AIT: aerobic interval training. 2.2. Somatic Measurements Body height was measured using an anthropometer (Seca 217, Seca, Hamburg, Germany) to the nearest 0.1 cm. Body weight and body composition were determined using a body composition analyzer (IOI 353, Jawon Medical, Seoul, Republic of Korea). In the measurement, body weight (BM), body mass index (BMI), lean body mass (LBM), body fat mass expressed in kilograms and percentages (FM) were determined. 2.3. Physical Activity The seven-day Physical Activity Recall (PAR) questionnaire was used to assess par- ticipants’ self-reported physical activity [23,24]. The subjects were instructed on how to complete the questionnaire and it was completed in the presence of the researchers, who clarified any doubts that arose. Physical activity was presented as total weekly energy expenditure in the period before the training intervention. 2.4. Anaerobic Capacity The Wingate test [25] was conducted on a bicycle ergometer (E834, Monark, Varberg, Sweden). The bicycle ergometer was connected to a computer and used software (MCE, JBA Staniak, Warsaw, Poland) to calculate the following indices: peak power (PP), mean power (MP), fatigue index (power decrease) (FI). After adjusting the saddle height, the subject began a 5 min warm-up with a load of 120 watts and a cadence of 60 revolutions per minute, during which the participant performed two (in the 2nd and 4th minute) maximum accelerations lasting about 5–6 s. Between
calculate the following indices: peak power (PP), mean power (MP), fatigue index (power decrease) (FI). After adjusting the saddle height, the subject began a 5 min warm-up with a load of 120 watts and a cadence of 60 revolutions per minute, during which the participant performed two (in the 2nd and 4th minute) maximum accelerations lasting about 5–6 s. Between the warm-up and the test was a 5 min recovery break, during which the participant stretched for 4 min. The main effort consisted of a 30 s sprint with a load of 7.5% of body weight. The test had a stationary start [26], and the participant’s task was to reach maximum pedaling speed (revolutions per minute) as fast
Appl. Sci.2025,15, 7953 5 of 16 as possible and then maintain it until the end of the test (an all-out effort). Throughout the test, each participant was vigorously and loudly encouraged by two test supervisors to perform supramaximal effort. During the test, the participant had to be in a sitting position. 2.5. Aerobic Capacity and Second Ventilatory Threshold Maximal oxygen uptake was measured by a direct method using a graded test. Based on the results of this test, the first (VT1) and second (VT2) ventilatory thresholds were also determined for each subject individually. The test was performed on a bicycle ergometer (Ergoline Ergoselect 100, GE, Bitz, Germany). Breath-by-breath gas analysis was performed using a Metalyzer 3B ergospirometer (Cortex, Leipzig, Germany). Each time before the test, the ergospirometer was calibrated, according to the manufacturer’s requirements (volume and gas calibration). The test began with a resting recording of the indicators tested for two minutes and then the subjects performed a 4 min warm-up with a load of 60 watts and a cadence of 60 revolutions per minute. Then, every 2 min, the exercise power was increased by 30 watts until a subjective volitional exhaustion. During the test, the participant was vigorously verbally cheered on. The following indices were measured in the test: heart rate (HR), oxygen uptake (VO2), pulmonary ventilation (VE), minute carbon dioxide production (VCO2), respiratory rate (RER), percentage of oxygen in exhaled air (FEO2), percentage of carbon dioxide in exhaled air (FECO2), ventilation equivalents for oxygen (VE/VO2) and carbon dioxide (VE/VCO2), and exercise power (P). After the test, the data obtained were analyzed; maximum oxygen uptake (VO2max) and ventilation thresholds (VT1 and VT2) were determined. The following criteria were used to determine VO2max: RER > 1.1, HR close to the age-predicted HRmax (±5 beats/minute), and no increase in VO2despite increasing load (plateau in VO2). All participants met the first two criteria. If no plateau was observed, but the other criteria were met, VO2peak was taken as VO2max [27]. Based on changes in measured physiological indices with increasing exercise power, ventilatory thresholds were determined. Ventilatory thresholds were determined using the respiratory
age-predicted HRmax (±5 beats/minute), and no increase in VO2despite increasing load (plateau in VO2). All participants met the first two criteria. If no plateau was observed, but the other criteria were met, VO2peak was taken as VO2max [27]. Based on changes in measured physiological indices with increasing exercise power, ventilatory thresholds were determined. Ventilatory thresholds were determined using the respiratory equivalents method [28,29]. The second ventilatory threshold was determined at the intensity at which VE/VCO2reached a minimum value and FECO2reached a maximum value, and a second breakdown of the linearity of pulmonary ventilation was observed. 2.6. Strength Training Resistance training was aimed at increasing strength and was performed in the gym using free weights (barbells) and body weight. Participants in the ST group performed exercises (squats, Bulgarian squats, deadlifts) at a controlled pace. The pace of the exercise was presented in seconds and describes the time of eccentric contraction, the pause between the eccentric and concentric phases, the time of concentric contraction, and the time of pauses after the end of the movement, e.g., 3/0/1/0. The recovery time between sets was 3–5 min, depending on the intensity of the effort. The frequency of training units was 3 times a week. On the first training unit, 1 repetition maximum (1 RM) was set for each participant for subsequent selection of exercise intensity. The load was increased until the subject was unable to perform the next repetition once. 1RM was determined only before the intervention and was not re-estimated during the intervention. Selection of training intensity (number of repetitions, percentage of maximum weight) was determined using Charles Poliquin’s table [30], depending on the established training goal. A detailed description of the strength training is shown in Table.
Appl. Sci.2025,15, 7953 6 of 16 Table 2.Training plan implemented by the strength group. Week Training Exercise Volume (Series×Reps) Intensity [%1RM] Pace (s) Recovery Time (s) I I 1. Barbell squat 5 ×5 70% 3/0/1/0 180 s 2. Push press 3 ×5 70% 3/0/1/0 180 s 3. Hip thrust 3 ×5 70% 3/0/1/0 180 s 4. Nordic curl 3 ×3 Body mass 4/0/1/0 180 s II 1. Deadlift 3 ×5 70% 3/1/1/0 180 s 2. Bulgarian squat 3 ×5 70% 3/0/1/0 180 s 3. Calf raise on leg press machine 3×5 70% 3/0/1/0 180 s 4. Abs wheel 3 ×5 Body mass 3/0/1/0 180 s III 1. Barbell squat 3 ×5 70% 1/2/1/0 180 s 2. Push press 3 ×5 70% 1/0/1/0 180 s 3. Hip thrust 3 ×5 70% 1/0/1/2 180 s 4. Nordic curl 3 ×3 Body mass 4/0/1/0 180 s II IV 1. Barbell squat 3 ×5 80% 3/0/1/0 240 s 2. Push press 3 ×5 80% 3/0/1/0 240 s 3. Hip thrust 3 ×5 80% 3/0/1/0 240 s 4. Nordic curl 3 ×3 Body mass 4/0/1/0 180 s V 1. Deadlift 3 ×5 80% 3/1/1/0 240 s 2. Bulgarian squat 3 ×5 80% 1/0/1/0 240 s 3. Calf raise on leg press machine 3×5 80% 3/0/1/0 180 s 4. Abs wheel 3 ×5 Body mass 1/0/1/2 180 s VI 1. Barbell squat 3 ×5 80% 1/2/1/0 240 s 2. Push press 3 ×5 80% 1/0/1/0 240 s 3. Hip thrust 3 ×5 80% 1/0/1/2 240 s 4. Nordic curl 3 ×3 Body mass 3/0/1/0 180 s III VII 1. Barbell squat 5 ×5 80% 3/0/1/0 240 s 2. Push press 3 ×5 80% 3/0/1/0 240 s 3. Hip thrust 3 ×5 80% 3/0/1/0 240 s 4. Nordic curl 3 ×4 Body mass 3/0/1/0 180 s VIII 1. Deadlift 3 ×5 80% 3/1/1/0 240 s 2. Bulgarian squat 3 ×5 80% 1/0/1/0 240 s 3. Calf raise on leg press machine 3×5 80% 3/0/1/0 180 s 4. Abs wheel 4 ×5 Body mass 1/0/1/2 180 s IX 1. Barbell squat 3 ×5 80% 1/2/1/0 240 s 2.
Description
This study compares strength training and aerobic interval training effects on physical performance.