1Titus Terwase Chior
2Florence Doolumun Chior
1Department of Physical And Health Education
College of Education Katsina-Ala Benue State Nigeria
2Department of Human Kinetics and Health Education Benue State University Makurdi Benue State Nigeria
This study was carried out against the background that most of the researches on children and youths have focused on aerobic power. Few researches on anaerobic power and specifically, leg power in Nigeria have focused on adult males and females or adult males or adult females or children or youths. The purpose of this present study was to determine sex and age differences in leg power of children and youths in Benue state. To achieve this, one thousand, seven hundred and eighty-eight (1,788) subjects made up of 655 (36.6%) males and 1,133 (63.4%) females in the primary and secondary schools in the three geo-political zones of the state were selected for the study. Anthropometric measurements were taken and the vertical jump test was used as an instrument for data collection. Descriptive statistics of mean (x) and standard deviation (SD) were used to analyze data. Also, the two-way analysis of variance (ANOVA) was used to test the hypotheses. All analyses were done on a micro computer using the Statistical Package for the Social Sciences (SPSS). The hypotheses were tested at 0.05 alpha level. The result showed no significant [(F1, 1769) = 1.597, p = .206] sex difference in leg power of children and youths in the state; but a significant [(F9, 1769) = 13.159, p = .001] age difference and a significant [(F8, 1769) = 7.661, p = .001] sex by age interaction difference in leg power of children and youths in Benue State. Within the limitations of the study, it was concluded that there is no significant sex difference in leg power of children and youths in the state; but there is a significant age difference in leg power of children and youths and a significant sex by age interaction difference in leg power of children and youths in the state.
Jumping is important in most sporting activities and some activities of daily living. For instance, some activities in field athletics, soccer, basketball, volleyball and handball require jumping (Musa & Toriola, 2006). Leg power can be looked upon as the force or energy exerted by the muscles of the leg. It is the ability of the muscles to generate high absolute force for short periods of time for the performance of anaerobic work. Praagh (2007), stated that direct measurements of the rate or capacity of anaerobic pathways for energy turnover presents several ethical and methodological difficulties. Therefore, rather than measure energy supply, exercise scientists have concentrated on measuring short-term power output by means of standardized protocols, such as running tests, cycling power test, or vertical jump tests. The vertical jump test is widely used to determine lower body anaerobic power because of absence of direct measurement devices like the force platform in many laboratories.
Armstrong, Welsman and Chia (2000), reported that despite recognition that physical activity patterns of young people are characterized by short burst, predominantly anaerobic activities; data estimating anaerobic performance of young people are scarce. According to the authors, direct measurement of anaerobic performance of young people is currently difficult and research has focused on the assessment of short-term power output. The Wingate anaerobic test (WAnT) which allows for the determination of peak power (PP) and mean power (MP) usually over a 30 second test period has emerged as the most widely used test of the short term power output (Musa, Ismaila & Mohammed, 2003). Anaerobic power is the ability to produce energy by the ATP-PC energy pathway (Nieman, 2003). Housh, Housh and DeVries, (2003), in comparing physiological functioning and athletic performance, maintained that males are stronger than females. According to the authors, females have less MP and PP than the males, when expressed in both absolute and relative terms. They concluded that males tend to be stronger than females, but when strength is expressed per unit of muscle mass, the differences attenuate. The physiological characteristics of females have often been compared with those of their male counterparts. Such comparisons according to Musa (2005), have led to the conclusion that in general, males tend to manifest greater muscular strength, higher anaerobic characteristics, greater lean body mass (LBM) and lower relative body fat. It has been observed that the gender difference in lower body strength and power output is a function of the stature, LBM, and force development differences in women and men. Again, Musa (2005), attributed the low anaerobic capacity of females partly to the smaller overall muscle mass of the average female compared with that of the average male.
Throughout the life span of humans, physical performance and physiological functioning improve rapidly from early childhood to a maximum somewhere between the late teens and about thirty years of age. Then in most cases, decline occurs during adulthood that becomes more rapid with increasing age (Housh, Housh & DeVries, 2003). Peak anaerobic power per unit body mass in boys shows in general an increase with age from childhood into adolescence. Plowman and Smith (2003), reported that in boys PP increases consistently from age 10 to young adulthood. Data on anaerobic fitness of Nigerian children are scarce and possible gender differences in these children are yet to be conclusively established.
Statement of the Problem
Anaerobic fitness in children and youths has not received the same attention from researchers as aerobic fitness. This is surprising given the level of anaerobic energy used during the period of childhood and adolescence. During physical activities, children and youths are more attracted to short-burst movements than to long-term activities. There are evidence indicating that the trend in motor performance of school-age children is towards improvement with age for both boys and girls, with the average performance of the boys usually exceeding the average performance of the girls at each age (Morris, Williams, Atwater & Wilmore, 1982). It has been observed (Plowman & Smith, 2003), that anaerobic power and capacity improve with growth and development.
Data on anaerobic fitness of children and youths have been reported in developed nations (Morris, Williams, Atwater & Wilmore, 1982; Mayhew & Salm, 1990, Armstrong, Welsman & Chia, 2000; Patterson & Patterson, 2004). In Nigeria, studies that have examined anaerobic power are scarce, limited to adults and mostly utilized small samples (Musa, Ismaila & Mohammed, 2003; Musa, 2005; Musa & Toriola, 2006).
In Benue state, children and youths that are supposedly the vibrant group of people are poor in general fitness including anaerobic fitness. This is seen from their inability to carryout short-term physical tasks with vigour and enthusiasm. This is observed from their performance in activities like running, jumping and throwing when compared with that of their counterparts in other parts of the country during schools’ sports festivals, such as the All – Primary or All – Secondary School Games Festival. Taking into cognizance the fact that Benue state is an agrarian state and that children and youths are most times engaged in farm activities, the study was designed to examine sex and age differences in leg power of children and youths in Benue State.
Purpose of the Study
The purpose of the study was to examine the sex and age differences in leg power of children and youths in Benue state. Specifically the study was to do the following:
- Examine whether there will be any sex and age difference in leg power of children in Benue state;
- examine whether there will be any sex and age difference in leg power of youths in Benue state; and
- examine whether there will be any sex by age interaction difference in leg power of children and youths in Benue State.
The following hypotheses were tested:
- There is no significant sex difference in leg power of children and youths in Benue state.
- There is no significant age difference in leg power of children and youths in Benue State.
- There is no significant sex by age interaction difference in leg power of children and youths in Benue state.
The study was conducted using an ex post facto design. Also called causal – comparative design, it seeks to investigate possible cause – and – effect relationship between the dependent and independent variables. This design was considered suitable as the study sought to determine sex and age differences in leg power of children and youths.
The population for the study comprised all male and female children and youths in the primary and secondary schools in Benue state, with a total population of one million, two hundred and one thousand and six (1,201,006), made up of seven hundred and seventy three thousand, five hundred and six (773,506) pupils (State Universal Basic Education, 2008) and four hundred and twenty seven thousand, five hundred (427,500) students (Teaching Service Board, 2008), as cited by Agee (2007).
A total of one thousand, seven hundred and eighty-eight subjects, made up of six hundred and fifty-five (655) males and one thousand, one hundred and thirty-three (1133) females were selected for the study, in accordance with the recommendations of Kregcie, Margon and Daryle (1970). Using a multistage sampling technique (performing more than one round of cluster sampling and finally randomly selecting elements from the chosen cluster), in the first stage, eight (8) local governments (Katsina Ala, Ushongo and Kwande in Zone A; Makurdi, Gwer-West and Buruku in Zone B; Otukpo and Oju in Zone C were selected). In the second stage, nineteen (19) schools (ten (10) primary and nine (9) secondary) were selected across the state as follows; four (4) primary and three (3) secondary schools each from Zones A and B; and three (3) primary and 2 secondary schools from Zone C. Thereafter, subjects were randomly selected from each school. These one thousand, seven hundred and eighty-eight (1788) subjects formed the sample for the study.
The major instrument used for the study was the vertical jump test. This is a test of leg power in which the difference between a stand reach height and jump height is the score. Other instruments used were:
- Digital bathroom weighing scale (Tanita, HD-309, Creative Health products, M1, USA). This was used to determine the weight of the subjects.
- Tape measures (Xiaoniychiye, XN-266, China). This was used to measure the height of the subjects on an improvised stadiometer (wall).
- This is an improvised wall that was used to take the subjects’ stand reach and jump height.
- Data sheet. A profoma that was used to record the scores of the subjects.
The instrument (vertical jump test) used was one that had been tested and its reliability ascertained for the measurement of anaerobic power. Clarke (1967), reported a reliability coefficient of 0.85. Plowman and Smith (2003) reported a reliability coefficient of 0.92. The instrument was equally used for the pilot study and a reliability coefficient (Cronbach Alpha coefficient) of .97 was obtained. The instrument was therefore suitable for the present study.
Subjects’ physical characteristics were measured according to Ross and Marfell Jones’s standard protocol (Musa, Ibrahim & Toriola, 2002). Their weights in kilograms were taken using a portable digital scale with provision for calibration and recorded to the nearest 0.1kg. Also their heights were measured using the protocol of the International Society for the Advancement of Kinanthropometry (ISAK, 2002). Subjects stood with feet together on a cemented floor, the upper back, buttocks and heels touching the wall, head held erect and eyes looking forward. The point of the greatest height (vertex) to the nearest 0.1 cm was marked off on the wall and a measuring tape used to take the measurement. The subjects’ body mass index (BMI) was derived as a ratio of the weight in kilograms to height in meters squared, according to Plowman and Smith (2003).
Jump height (using the squat jump protocol) was measured to the nearest centimeter according to Patterson and Peterson (2004). The subjects stood close, with the side parallel to the wall and the dominant hand fully extended up so that the highest possible point on the wall was reached. Keeping the feet flat on the ground, the point of the fingertips was marked or recorded. This is called the standing reach height. The subject then squatted away from the wall, and jumped upwards and attempted to touch the wall at the highest point of the jump. The difference in distance between the standing reach height and the jump height was the score. Each subject was allowed three trials with a minute’s rest between trials. The best of the three trials was used as the dependent measure. This is because Plowman and Smith (2003), have reported that the height of a vertical jump is an acceptable indicator of anaerobic power.
Descriptive statistics (Mean and Standard deviation) was used to describe the physical characteristics and performance data of the subjects on the vertical jump. Analysis of variance (two – way ANOVA) was used to determine the differences in leg power of the subjects. Where the F – ratio was found to be significant, the Post-hoc comparison (Bonferroni test of multiple comparisons) was performed using the computer Statistical Package for the Social Science (SPSS) to determine the differences. All analyses were performed at 0.05 level of significance.
The data collected were subjected to descriptive and statistical analysis of mean, standard deviation and analysis of variance (2-way ANOVA) to answer the research questions and test the hypotheses. The physical and performance characteristics of participants are presented in Table 1, while the 2-way ANOVA summary table of leg power is presented in Table 2.
Youths were better than children on all physical and performance characteristics. The youths had higher values on age (14.1±1.6), height (152.6±11.1), weight (44.3±9.6) and vertical jump (23.3±7.3) against those of children’s age (10.4±1.6), height (139.1±8.0), weight (34.1±10.1) and vertical jump (20.9±7.1).
The descriptive analysis also showed that male children were better (20.9±6.5) than female children (18.0±7.1) in leg power; while female youths were better (24.2±6.9) than male youths (22.0±7.1) in leg power.
The present study set out to determine the sex and age differences in leg power of children and youths in the state. The result of the study shows no significant [(F1, 1769) = 1.597, p = .206] sex difference (p>0.05) in leg power of children and youths in the state. This result is inconsistent with that of Maud and Shultz (1986), who in a study of 50 male and 52 female students on anaerobic power and capacity tests found that males were better (.70±.12) than females (.62±.13) in vertical jump. The result does not support an earlier study by Musa (2005) who found significant sex difference in PP and MP of 76 male (639.4±130.2; 492.8±115.1) and 40 female (553.7±121.7; 419.0±101.2) university students. The result of this study is in conflict with that reported by Housh, Housh and DeVries (2003), that females tend to have lower anaerobic capabilities than males. In the same manner the result of the present study is at variance with the report by Plowman and Smith (2003), that in general anaerobic characteristics of females are lower than those of males during the young and middle-aged adult years. Also, the present study does not support that of Hazir and Kosar (2007), who reported that males had significantly greater peak power than the females. This result is surprising given that results of earlier researches have indicated sex differences in anaerobic capacity of males and females. This may be explained by differences in the ages of the samples (adults) or the utilization of small samples in those studies and a larger one in the present study.
The result of the present study is however consistent with that of Morris, Williams, Atwater and Wilmore (1982), who in a study of age and sex differences in motor performance of 3 through 6 year old children found that age was related more to performance than was gender. The study also supports the earlier findings by Patterson and Patterson (2004), that jump height was similar in both sexes throughout the age range of 21 to 30 years.
The present study also set out to determine age difference in leg power of children and youths in Benue State. From the analysis the result shows a significant [(F9, 1769) = 13.159, p = .001] age difference (p<0.05) in leg power of children and youths in the state. This result is consistent with that of Musa, Ismaila and Mohammed (2003), who in their study on age differences in anaerobic power found significant age differences for <24yr (21.7±1.6), 25-29yr (27.2±1.0) and >29yr (34.3±1.6). The present study also supports earlier reports by Wilmore and Costill (1999), Plowman and Smith (2003), and Musa (2005), that anaerobic power and capacity improve with growth and development. The findings of the study also support their assertion that peak power increases consistently from age 10 to young adulthood. The present study is however inconsistent with the result of Haruna (1991) that anaerobic power is not influenced by age. It is also not consistent with insignificant age difference observed by Musa, Ismaila & Mohammed (2003), in the vertical jump performance of female university students. This variance may not be unconnected with the fact that subjects of different age groups were used in these studies or that they made use of only female subjects in their study. Moreover, there are also differences in the settings for these studies.
The study equally set out to determine the sex by age interaction difference in leg power of children and youths in Benue State. The result of analysis of variance shows a significant [(F8, 1769) = 7.661, p = .001] sex by age interaction difference (p<0.05) in leg power of children and youths in the state. This result is consistent with that of Armstrong, Welsman and Chia (2000), in their study on short-term power output in relation to growth and development using 417 subjects. They reported a significant age by sex interaction in the MP of boys and girls. The result was expected as both males and females at these periods of their development do not differ significantly in their activities.
Within the limitations of the study, the following conclusions were drawn;
That both male and female children and youths in the state have similar abilities in leg power; there exist age difference in leg power of children and youths in the state, that is to say that the performances of children and youths in the state on the vertical jump vary according to their ages and that there exist sex by age interaction difference in leg power of children and youths in Benue State, but these differences are not consistent across gender.
Based on the above conclusion, the study recommended that since both male and female children and youths in the state have similar abilities in leg power, meaningful training programmes in the schools all-year round will be useful in helping them to develop the strength, power and endurance needed for the short-term physical tasks with vigour like their counterparts elsewhere. This will enable the children and youths in the state to consequently excel during sports meets and effectively perform power-type activities in their daily life activities.
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