TY - BOOK
T1 - Fitness and Health Effects of Frequent Intense Training in 8-10-Year Old Danish Children
AU - Larsen, Malte Nejst
N1 - CURIS 2016 NEXS 328
PY - 2016/11
Y1 - 2016/11
N2 - Physical activity for children has been much debated in recent years. Everyone has seemed to agree
that it is important for children to exercise for the sake of physiological health, but cognitive
functions and psycho-social behaviour are now also considered to be affected by physical activity.
In fact, the evidence of beneficial effects convinced Danish politicians to design a school
curriculum with 45 minutes of physical activity every day, which should enable every child to fulfil
the recommendations of 60 minutes of moderate to vigorous physical activity (MVPA) every day
when supplemented with organised and unorganised leisure time activities. The issues addressed in
this thesis are the physiological responses to small-sided football and other high-intensity activities.
Paper I showed that recreational small-sided football games are highly intense for 9-12-year-old
boys and that 5v5 provides for great involvement of all players compared to 8v8. For U10 players,
no difference was found between 5v5 and 8v8 games in total distance covered (1754±237 (±SD) vs
1771±314 m, P=0.650, d=0.06), peak speed (18.5±1.5 vs 18.9±1.7 km∙h-1, P=0.188, d=0.24) and
player load (251±44 vs 239±57 arbitrary units (AU), P=0.055; d=0.24). During 5v5 games, higher
mean HR (174±10 vs 168±12 bpm, P=0.001, d=0.59) and number of technical actions (65.1±24.0
vs 36.9±20.4, P<0.001, d=1.27) were observed compared to 8v8 games.
Paper II showed that 8-10-year-old school children active in sports clubs had better (P<0.05)
YYIR1C (33%, 767±26 vs 575±29 m), 20-metre sprint (3%, 4.33±0.03 vs 4.48±0.04 s),
coordination (6%, 68±1 vs 72±1 s) and balance test performances (9%, 19.3±0.5 vs 21.2±0.7
falls/min) and lower fat mass index (FMI) (16%, 3.8±0.1 vs 4.5±0.2 kg(fat)·m-2) than children not
active in sport clubs. Ball game players had better (P<0.05) YYIR1C (38%, 925±39 vs 671±28 m),
20-metre sprint (4%, 4.25±0.03 vs 4.42±0.04 s) and coordination test performances (5%, 65±1 vs
69±1 s), along with higher (P<0.05) lean body mass (LBM) (5%, 24.00±0.22 vs 22.83±0.25 kg) and
whole-body BMD (2%, 0.90±0.00 vs 0.88±0.00 g/cm2) compared to children active in other sports.
Paper III and IV described the long-term training effects of frequent intense small-sided ball games
(SSG), interval running (IT) and circuit strength training (CST) for 8-10-year-old school children.
Analysis of baseline-to-10-months change scores showed between-group differences in favour of
the 3x40 minute interventions in whole-body aBMD (SSG vs CON: 8 mg/cm2, 95%CI: 3-13; CST
vs CON: 7 mg/cm2, 95%CI: 2-13, P<0.05) and leg BMC (SSG vs CON: 11 g, 95%CI: 4-18; CST vs
CON: 11 g, 95%CI: 3-18, P<0.05). SSG produced higher change scores in leg aBMD compared to
CON and CST (SSG vs CON: 19 mg/cm2, 95%CI: 11-39, P<0.001; SSG vs CST: 12 mg/cm2,
95%CI: 3-21, P=0.017), and CST produced higher change scores in whole-body BMC compared to
CON (CST vs CON: 25 g, 95%CI: 10-39, P<0.05). Both types of training resulted in higher change
scores compared to CON in postural balance (SSG vs CON: 2.4 fewer falls/min, 95%CI: 0.3-4.5,
CST vs CON:3.6 fewer falls/min, 95%CI: 1.3-5.9, P<0.05) and jump length (SSG vs CON: 10%,
95%CI: 5-16%; CST vs CON: 9%, 95%CI: 3-15%, P<0.05) and that 5x12 minutes IR had positive
effects (P<0.05) on 20-metre sprint performance (IR vs CON: 154 ms [95% CI 61–241 ms]).
In conclusion, the heart rates and distances covered with high-intensity running are high in youth
football matches irrespective of the game format and level of play. Playing with fewer players on
smaller pitches results in minor changes to physical loading but increases the technical involvement
of players at elite and recreational level, which supports the use of small-sided games for youth
players in football clubs. The exercise intensity (HR as well as player load) was also shown to be
high during SSG in a school setting, as well as during IR and CST.
Results from the intervention study demonstrate that significant structural and functional
musculoskeletal adaptations can be achieved from well-controlled high-intensity training in a
school-based setting, especially from 3x40 minutes of SSG and CST. The overall fitness effects of
the low-volume training (5x12 minutes of SSG or IR) were limited, yet positive effects were seen in
sprint performance in the interval running group and in cardiovascular strain during submaximal
exercise in the ball game group as well as in the interval running group, among those with low
aerobic fitness levels.
Future studies will investigate other aspects of using small sided ball games in schools as part of
physical education.
AB - Physical activity for children has been much debated in recent years. Everyone has seemed to agree
that it is important for children to exercise for the sake of physiological health, but cognitive
functions and psycho-social behaviour are now also considered to be affected by physical activity.
In fact, the evidence of beneficial effects convinced Danish politicians to design a school
curriculum with 45 minutes of physical activity every day, which should enable every child to fulfil
the recommendations of 60 minutes of moderate to vigorous physical activity (MVPA) every day
when supplemented with organised and unorganised leisure time activities. The issues addressed in
this thesis are the physiological responses to small-sided football and other high-intensity activities.
Paper I showed that recreational small-sided football games are highly intense for 9-12-year-old
boys and that 5v5 provides for great involvement of all players compared to 8v8. For U10 players,
no difference was found between 5v5 and 8v8 games in total distance covered (1754±237 (±SD) vs
1771±314 m, P=0.650, d=0.06), peak speed (18.5±1.5 vs 18.9±1.7 km∙h-1, P=0.188, d=0.24) and
player load (251±44 vs 239±57 arbitrary units (AU), P=0.055; d=0.24). During 5v5 games, higher
mean HR (174±10 vs 168±12 bpm, P=0.001, d=0.59) and number of technical actions (65.1±24.0
vs 36.9±20.4, P<0.001, d=1.27) were observed compared to 8v8 games.
Paper II showed that 8-10-year-old school children active in sports clubs had better (P<0.05)
YYIR1C (33%, 767±26 vs 575±29 m), 20-metre sprint (3%, 4.33±0.03 vs 4.48±0.04 s),
coordination (6%, 68±1 vs 72±1 s) and balance test performances (9%, 19.3±0.5 vs 21.2±0.7
falls/min) and lower fat mass index (FMI) (16%, 3.8±0.1 vs 4.5±0.2 kg(fat)·m-2) than children not
active in sport clubs. Ball game players had better (P<0.05) YYIR1C (38%, 925±39 vs 671±28 m),
20-metre sprint (4%, 4.25±0.03 vs 4.42±0.04 s) and coordination test performances (5%, 65±1 vs
69±1 s), along with higher (P<0.05) lean body mass (LBM) (5%, 24.00±0.22 vs 22.83±0.25 kg) and
whole-body BMD (2%, 0.90±0.00 vs 0.88±0.00 g/cm2) compared to children active in other sports.
Paper III and IV described the long-term training effects of frequent intense small-sided ball games
(SSG), interval running (IT) and circuit strength training (CST) for 8-10-year-old school children.
Analysis of baseline-to-10-months change scores showed between-group differences in favour of
the 3x40 minute interventions in whole-body aBMD (SSG vs CON: 8 mg/cm2, 95%CI: 3-13; CST
vs CON: 7 mg/cm2, 95%CI: 2-13, P<0.05) and leg BMC (SSG vs CON: 11 g, 95%CI: 4-18; CST vs
CON: 11 g, 95%CI: 3-18, P<0.05). SSG produced higher change scores in leg aBMD compared to
CON and CST (SSG vs CON: 19 mg/cm2, 95%CI: 11-39, P<0.001; SSG vs CST: 12 mg/cm2,
95%CI: 3-21, P=0.017), and CST produced higher change scores in whole-body BMC compared to
CON (CST vs CON: 25 g, 95%CI: 10-39, P<0.05). Both types of training resulted in higher change
scores compared to CON in postural balance (SSG vs CON: 2.4 fewer falls/min, 95%CI: 0.3-4.5,
CST vs CON:3.6 fewer falls/min, 95%CI: 1.3-5.9, P<0.05) and jump length (SSG vs CON: 10%,
95%CI: 5-16%; CST vs CON: 9%, 95%CI: 3-15%, P<0.05) and that 5x12 minutes IR had positive
effects (P<0.05) on 20-metre sprint performance (IR vs CON: 154 ms [95% CI 61–241 ms]).
In conclusion, the heart rates and distances covered with high-intensity running are high in youth
football matches irrespective of the game format and level of play. Playing with fewer players on
smaller pitches results in minor changes to physical loading but increases the technical involvement
of players at elite and recreational level, which supports the use of small-sided games for youth
players in football clubs. The exercise intensity (HR as well as player load) was also shown to be
high during SSG in a school setting, as well as during IR and CST.
Results from the intervention study demonstrate that significant structural and functional
musculoskeletal adaptations can be achieved from well-controlled high-intensity training in a
school-based setting, especially from 3x40 minutes of SSG and CST. The overall fitness effects of
the low-volume training (5x12 minutes of SSG or IR) were limited, yet positive effects were seen in
sprint performance in the interval running group and in cardiovascular strain during submaximal
exercise in the ball game group as well as in the interval running group, among those with low
aerobic fitness levels.
Future studies will investigate other aspects of using small sided ball games in schools as part of
physical education.
UR - https://rex.kb.dk:443/KGL:KGL:KGL01009283216
M3 - Ph.D. thesis
BT - Fitness and Health Effects of Frequent Intense Training in 8-10-Year Old Danish Children
PB - Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen
CY - Copenhagen
ER -