EFFECTS OF CYCLE ERGOMETER RESISTANCE TRAINING ON STRENGTH AND POWER

IN 13 YRS OLD BASKETBALL PLAYERS

GALAZOULAS CH., VAMVAKOUDIS E., ZAGGELIDIS S.,

 TSADIMAS V., METAXAS TH.

Laboratory of Ergophysiology – Ergometry

Department of Physical Education of Sport Science

Aristotle University of Thessaloniki

Key words: Strength development, prepubertal boys, isokinetic strength

isometric strength, basketball players.

Introduction

The participation of young basketball players in organized sports events has heavily developed during recent years. Resistance training in young players has seen improvements in performance. Thus, this form of training has become more popular in the world of competitive sport (Micheli 2001).

Despite the obsolete argument that young children could not profit from resistance training due to low levels of androgens, modern medical results indicate that the participation of prepubertal boys in an appropriately planned and efficiently supervised resistance training programme may contributes to an improved performance (American Orthopaedic Society for Sports Medicine, 1988; American College of Sports Medicine, 2000).

Research that took place during the last decade offers new evidence and proposes that children can actually increase their muscle strength levels beyond that of their age related untrained peers, through participating in resistance training programmes over a prolonged period of time (Blimkie, 1993; Falk&Tenenbaum, 1996; Sale & MacDougall 1981, Weltman et al., 1986; Sailors & Berg, 1987, Ramsay et al. 1980).

Different combinations and repetitions of sets and the different ways of training are considered safe and effective ways to develop muscular strength in prepubertal boys. Nevertheless, the load or the resistance used seems to be one of the most significant variables. On the other hand introduction of strength training programmes that are designed for adults can be potentially dangerous to children as the increased loads may damage growth plates within the bones (Brady et al., 1982 & Legwold, 1982).

Given that muscles are crucial to health and the development of natural abilities of any individual, it would be helpful if we could give specific advice to coaches and P.E. teachers with regards several resistance training programmes for young boys. It would also be advised to follow closely the safety rules. (American Association of Health, Physical Education, Recreation and Dance 1981, President's Council on Physical Fitness and Sports1987)

The aims of this paper therefore are to examine the influence of a training programme on a cycle-ergometer with a gradually increased resistance on the maximum isokinetic muscle strength of the quadriceps and biceps femoris. Furthermore, the maximal isometric muscle strength of the quadriceps muscle group in prepubertal boys will be assessed for improvements.

Methodology

Twenty four healthy basketball players, aged 13, partook in this research. Participants were divided into two groups with an experimental exercise group A (n=13) and a control group E (n=11). The features of the participants are presented in Table 1.

The biological age of participants was evaluated, based on their secondary features, with regards the five stages of development, as described by Tanner (1962). The genitals were the feature that was predominately examined followed by pubic hair growth. All players who participated in this programme were considered to belong to the 3^rd development phase (prepubertal). Participants were examined by a paediatric doctor and were informed about the programme they were to undertake. Consent for participation in the study was also sought and given by parents and guardians of the respective players. Participants all played for the same basketball team so that there would not be any differentiation in the training programme. During the time the players were partaking in the experiment they also participated in matches and training sessions for the team. Three players who participated in 80% of the sessions were not included in the sample. All players had at least trained for the last 2 years. The participation in the sessions was voluntary.

Measurements took place in the Laboratory of Ergophysiology, Department of Sports Science and Physical Education at the Aristotle University of Thessaloniki under normal conditions of temperature and humidity. Participants who failed to attend more than 4 times (i.e. 14%) during the experimental time frame would also be excluded from the study.

Procedure

Peak isometric and isokinetic torque of the quadriceps and the hamstring muscles was assessed for both legs using an isokinetic dynamometer (Cybex II, Lumex, Inc., Ronkokoma, NY 11779) at various angular velocities (0, 30, 60, 120, 180, and 300°·s^–1). A gravity-effect correction was done as reported elsewhere (26).

The session began with an 8 to 10 minute warm-up on a cycle-ergometer with a resistance set at 50 Watts, followed by static stretching of the hamstring and quadriceps muscle groups. Following the warm-up participants were informed about the procedure.

They sat on the dynamometer having the knee flexed at a 90° (0° = fully extended), with the examined member being stabilised with restraint straps. The arms crossed across the chest and the opposite member was free. The resistance arm of the dynamometer was positioned 5cm above the ankle and the axis of the dynamometer was in the same line with the anatomic turning axis of the knee. Participants were allowed a habituation period before testing. All participants had the day proceeding the testing session free from training. The initial angular speed started with the smaller resistance (300°·s^-1) and was gradually increased reaching maximally 30°·s^-1). The session started with the extension of the leg and then with flexion.

Every angular speed included three efforts, which were executed in intervals of 30 sec and the value of the better effort was registered. The break between the angular speeds was 60 sec. The extension of the quadriceps started from 90^o (knee flexed) until 0^o (knee extended). The flexion of the hamstrings was performed in reverse (0^o to 90^o).

The maximal isometric force of the quadriceps was measured at 60^o of the knees flexion. Three different maximum efforts were carried out to determine the highest peak-torque value. The break between the efforts was 60^osec. The maximum isometric strength was registered every 0,4 sec and the total time of registration was 7,9 sec.

Maximal Exercise Test

Before the training, participants were asked to perform a maximum effort on the cycle-ergometer (Monark Sweden) at a cadence of 50 revolutions per minute, so as to determine the maximum load and the maximum heart rate.

In order to determine both workload and heart rate during the submaximal and maximal exercise test, the initial workload was set to 50 W. This workload was previously determined by means of a work test on a cycle ergometer. In the first workload, participants cycled for 6 min. Thereafter, the workload was set at 25 W with a stepwise increase every minute until exhaustion. During maximal exercise the test-pedaling rate was set at 50 rpm. To control the heart beat we used a special heart rate monitor (Sport Tester PE 3000 Polar Electro), whilst checking using the maximal exercise in accordance with the Borg scale.

Training programme

The training was in intervals and included rigorous and smooth muscular effort of a total duration of 50 to 55 minutes. Training took place three times a week for 10 weeks. The programme started with the 8-10 minutes warm up and included running and free exercises so that more muscle groups would be used.

Following the warm up, the training programme was applied alternatively with intensive and relaxed effort. The intense muscular effort was individually set and was repeated 6 times on the cycle-ergometer. Every intense effort lasted for 2 minutes with the gradually increased every 30 seconds by the participant who turned the resistance dial. Initial loading was set at approximately 65% of the maximum ability. Loads were then increased by 10% in the following 30sec and by 5% every 30 seconds in the following minute. The resistance of the load was checked by the corresponding heart rate, which was between 80 to 85% of the maximum. Loads were increased every week by 5 to 10% and were estimated by the maximum load every individual performed at the end of the week testing.

Between the intense intervals a less intense period was included. This lasted 4 minutes every time and corresponded to 50 to 65% of the maximum heart rate. This less intense section included exercises to reinforce the abdominal and back extension exercises, stretching exercises of the lower body and exercises to control a basketball. The training programme finished every time with a cool down which lasted 8 to 10 minutes. The cool down consisted of low level walking. Heart rates during this period of recovery were recorded via a heart rate monitor (Sport Tester PE 3000 Polar Electro) which every individual had attached to his chest.

Statistical analysis

To check the hypothesis of this research an analysis of variance with two factors with repeated measurements were selected. The first factor was the kind of exercise the participants were doing, i.e. exercise group or control group. The second factor was the measurements in two levels (pre- and post). Regarding the differences observed between the groups this was processed further by utilising t-tests and paired or independent observations depending the case. For all the dependant factors the average and the deviation were estimated. The differences were seen as statistical significant in level p<.05.

Results

Before the beginning of the training programme the maximum isokinetic strength of the extensors and flexors of the knee were measured together with the angular speeds. Maximum isometric force of the extensor muscles of the knee, were also measured approximately in the two groups A and E.

After the training period that lasted 10 weeks, the maximum isokinetic strength of the extensors and the flexors of the knee increased gradually (p<.001) at all angular speeds (30, 60, 120, 180, 300^o·s^-1) in all the participants of group A. On the contrary, the participants of group E maximum isokinetic strength increased significantly in the extensors (p<.01) in the high angular velocities (180, 300^o·s^-1) and in the flexors in the middle 120^o·s^-1) (p<.05) and in the high angular speeds (180, 300^o·s^-1) (p<.01 and p<.05). The maximum isokinetic strength in the two muscular groups in the low angular speeds (30, 60^o·s^-1) (Fig. 1-2) remained unchanged.

Both groups presented improvements in their isokinetic muscle strength. Nevertheless, the improvement in group A was much higher comparing to group E. In group A, the following results were evident in the extensors: 9,6% to 11,4%, flexors 5,6% to 22,3%, while in group E: extensors 1.4% to 1,7%, flexors 4,8% to 10,8% (Fig. 4).

The maximum isometric strength increased significantly (p<.001) only in the group A, while in the control group, group E, the levels were the approximately the same (Fig. 3).

• Table 1

Physical, Descriptives and Anthropometric Characteristics for trained (A)

 and Control groups (C) before and after strength training

(Values are Mean ± SD)

Training group (n=13) Control group (n = 11) Variables Before After Before After Height (cm) 179.2±6.5 180.2±6.4 180.6±7.7 181.4±7.6 Weight (kg) 73.1±11.5 74.1±11.4 72.9±9.7 73.5±9.1 HR (b/min) 68.1±10.1 64.7±7.6 63.9±7.3 61.4±4.9 sBP (mmHg) 116.5±6.8 113.5±4.4 110.6±11.5 109.7±10.2 dBP (mmHg) 62.6±9.1 61.6±6.8 62.4±11.8 60.9±10.1 Tanner's stage 3 3 3 3

Figure 1 - Isokinetic peak torque values (Nm) of quadriceps for trained and control groups at angular velocities, 30, 60, 120, 180, 300^o·s^-1,

 pre- and post- training period. (Values are means ±SE)

Figure 2 - Isokinetic peak torque values (Nm) of hamstrings for trained and control groups at angular velocities, 30, 60, 120, 180, 300^o·s^-1,

 pre- and post- training period.(Values are means ±SE)

Figure 3 - Isometric peak torque values (Nm) of quadriceps for trained and control groups, pre- and post- training period. (Values are means ±SE)

Figure 4 - Isokinetic peak torque (%) of quadriceps and hamstrings in training

and control groups

Discussion

The most significant outcome of this research was that the strength training which lasted 10 weeks and applied a high load to the participants using the cycle-ergometer improved significantly the isokinetic strength of the extensors and flexors muscles of the knee when using low angular speed, as well as the isometric strength in the prepubertal basketball players.

The results of this study cannot be compared with the results of other research concerning young players. However, they conform to the results concerning non trained boys at the prepubertal and pubertal age (Zakas 2004). They also conform to similar research which mentioned significant increases in the muscular strength in prepubertal boys (Pfeiffer and Francis 1986, Weltman et al. 1986, Ramsay et al. 1990, Blimkie 1993, Faigenbaum et al, 1996, Zakas 2004), where several programmes of muscular strength were used using different means to produce resistance.

Improvements in the isokinetic as well as the isometric force are in accordance with the research results from Ramsay et al (1990) in non trained boys prepubertal age, when they applied programmes of muscular strength which lasted 20 weeks. Furthermore results confirm previous research by Hasan (1991) and Blimkie et al (1993). Improvement in the isometric muscular strength in overweight women also mentioned in the research of Mandroukas et al. (1984) after having applied programmes of muscular strength using high loads in a cycle-ergometer. This programme lasted 12 weeks. Further research by Macaluso et al (2003) in aged women, which lasted 12 weeks, using a mechanical cycle-ergometer and increasing resistances, found improvements in isokinetic muscular strength as well as isometric muscular strength during the first 8 weeks. Beyond this time no improvement was registered.

The results in group E cannot be compared with the results of the other research. However Weltman et al. (1986) found significant improvement in the extension of the elbow in the control group in the prepubertal age, where the participants were competing in basketball and in ice hockey. In this research all participants in group E participated in all training sessions and in all basketball games. The improvements of these players in this group may be due to the systematic training with their team or even due to their natural growing up Zakas (2004), also found significant improvements in the isokinetic strength of the extensors and flexors of the knee in non trained prepubertal and pubertal pupils who participated in physical educations program, while Carron and Bailey (1974) mention that the resistance in boys aged 10 to 16 show an average annual increase of 10.1%, a percentage that resembles the results from this study. To further clarify whether these improvements in the basketball in muscular resistance are due to the bodily factors or in the adaptations resulting from the training, more research is required.

The improvements seen in the isokinetic and isometric strength in group A maybe due to the neuromuscular adaptations, i.e. the trend of increased activities of moving units (Blimkie, 1989b, Bompa, 1993, Ramsay et al, 1990), the increase of the speed of muscular contraction as Van Cutsem et al (1988) argue, which happens after a dynamic training; or due to the changes in the combination of the stimulation-contraction of the muscle (Duchateau and Hainaut, 1984). It is not clear yet which factors influence the increase of the muscles in the prepubertal athletes, due to the difficulties in undertaking such research. Furthermore ethical consideration restricts the participation of children in certain research.

The use of cycle-ergometer for the improvement of the muscular resistance consist a significant alternative means for the athletes in developing ages, because this does not require specific facilities and because the health of children does not run any danger. One of the advantages of the cycle-ergometers is that several individuals can use them for training at the same time while been observed by the person in charge. The participants in their vast majority partook in the activity with enthusiasm and they wished to partake in future research.

Concluding, it could be said that the research revealed improvements of the maximum isokinetic and isometric strength, both of the anterior and posterior muscles of the thigh. This is a significant result for the athletes who are in their developmental age, because no specific type of training is required to improve these skills.

The results of this research can become the basis of the development of similar programmes for special populations, as the athletes of developmental ages, or the aged people.

Abstract

The purpose of the present study was to investigate the effects of strength training performed on a cycle-ergometer on isometric force and Isokinetic strength of young basketball players. Twenty-two (n=24) healthy prepubertal (13 years old) basketball players participated in this study. Subjects were divided into two groups, exercise A (n=13) and control E (n=11). Both groups participated in a basketball-training program (4 times per week) where the exercise group was additionally trained (3 times per week) in a cycle-ergometer program for a total of 10 weeks. Each training session comprised of warm-up (10'), 6 two minute periods of high loading (80 to 85% HR max), alternated with 4 minute intervals of lower intensity (50-65% of HR max), and concluded with a recovery period of 8–10 minutes stretching exercises lasting ~50 minutes total. The dynamometer used for the strength measurements was Cybex II (Lumex Inc., Ronkonkoma, NY, 11779). All basketball players were evaluated on knee-extensor and flexor maximal isometric and isokinetic strength of in angular velocities of 30, 60, 120, 180 and 300^o·s^-1, before and after the 10-weeks training period. The results showed that high loading resistance training in a cycle-ergometer, significantly improved (p<.001) knee-extensor and flexor isokinetic strength in all angular velocities as well as the maximal isometric strength compare to the E group. In conclusion the strength training protocol that was applied in the cycle-ergometer, in addition to the regular training program can improve isokinetic and isometric muscular strength in prepubertal basketball players.

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