Low back pain by young athletes; is practicing sports, prevention or a risk factor to develop low back pain?

Ziva Tavcar, Msc Human Movement Science
Clinique Valmont, Switzerland

Introduction
Low back pain is a common problem in a modern society and is present also among pre- and adolescents as well by young athletes. Relationship between low back pain and physical activity shows that physical and psychical factors of over active or inactive life-style lead among genetically predisposed individuals to a higher risk for low back pain. Thus better understanding of a problem, earlier diagnostic and right management prevent earlier apparition of recurrences and chronicity in adulthood.

Spinal pain
Spinal pain appears due to variety of symptoms, which are experienced at least once in a lifetime by approximately 80% of a general population [1]. Classification of spinal pain concerns affected region (cervical, thoracic, lumbar, or irradiation in the limbs), duration (acute, sub-acute, chronic), or level of functional disability [1]. Lumbar pain is determined as a pain, muscle tension or stiffness that occurs between the last thoracic vertebra and the lower gluteal folds, with or without leg pain [1–3]. Chronic low back pain appears more often by working population in adulthood [1] and fluctuates during time, appears at different occurrences with different intensities and disability [4]. The complexity of symptoms could be associated with physical, psychical and recently genetic factors, as well most efficiently managed using multidisciplinary approach [5].

Spinal pain is common problem also among children and adolescents [3,6]. A cross-sectional study of 806 pupils in Denmark shows that children between 8-10 years suffer more from thoracic pain and 14 to 16 old adolescents equally from thoracic and low back pain, all together with a monthly prevalence of 39% [6]. Another cross-sectional study done on 29.424 individuals shows that a lifetime prevalence of low back pain could increase between 12 to 18 years old for 49%, and appears 2 years earlier by girls than boys [3]. Pre-adolescent and adolescent population seems to be more susceptible to acute low back pain, due to macro- or micro-traumatic injuries mostly correlated to some specific sports disciplines [7,8].

Physical activity, inactivity and sport
At the beginning of human evolution men - hunter was looking for a food and he was highly active during a day. With farming and technological revolution, this habitude change. Today the food is only few meters away and it is not necessary to hunt and spent a day to find a food as millions years ago [9]. This becomes a main problem of today’s society, as the amount of daily physical activity proportionally drops and it is sometimes even neglected. Therefore it is important to understand what it is physical activity or inactivity and in what manner the first one could be applied on a regular basis.

Physical activity is defined as any body movement, provoked by muscles that for this use the energy from nutriments, metabolic changes boost also cardio-respiratory system [10]. Physical activities are all kinds of daily occupational, household, conditioning or sports activities. It could be daily commute with a bike, play with a child or spontaneous exercise during leisure time without rules [11]. In the contrary, inactivity determines postures or activities that require no or very little movement. A person does not move and body metabolism is not or it is minimally stimulated [11]. For example inactivity is sitting or lying for a long time, watching TV, spending time on the computer, use of vehicles to travel from one part to another.

However any kind of regular physical activity, performed and planned in advance, practiced or individually or collectively, at the known location with applied rules and competitions is known as sport. Sport could be practiced on a recreational or more competitive - performance basis [12].

Correlation between low back pain and physical activity
It seems that the important amount of competitive sports provokes low back pain and in the contrary to the excess of exercise, also inactivity, could be a risk factor of appraisal of low back pain [13]. Physical activity and low back pain are correlated in continuum U shape [14]. The highest or the lowest amount of physical activity, situated at the right or at the left extremity of U shape represents higher risk to develop low back pain in all populations; as well in non-athletes and athletes [14,15].

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Nevertheless there are contradictory evidences of positive or negative effects of physical activity or sports on low back pain and depend also from definitions used for both variables as well used measurement instruments [15,16].

This phenomenon has been further observed in a following part, where two 3-years longitudinal studies were analyzed and correlated with several protective and/or risk factors. The first study brings ahead a protective role of high intensity physical activity among schools children [6] and the second exposes risk factors of physical activity on apparition of low back pain symptoms with anatomical modifications observed by young athletes or non-athletes [7].

Wederkopp et al [16] measured the intensity of physical activity with MTI-accelerometers in a population of 9-year schoolchildren. It was observed that after 3 years 33% of children move in average 4.4 minutes per day, what represents low amount of daily physical activity. In the contrary 34% of children were high physically active and were moving 36 minutes per day. Low back pain was assessed with stratified interview and followed-up during 3-years. If comparing groups with low and high amount of physical activity after 3 years, the first group experienced increase of pain in any body parts for 27%, low back pain for 46% and decrease of pain in middle back for 25%, with overall 58% of experienced pain in more than one region. The authors conclude that a higher amount of physical activity in 9-year schoolchildren prevented low back pain 3-years later in the contrary those with lower amount of daily physical activity were 68% more exposed to develop low back pain.

Actually certain sports disciplines apply important mechanical loads on the spine that could be a risk factor for apparition of low back pain. Kujala et al [7] exposed this risk factor within 3-year longitudinal study on a population of 98 adolescents, aged around eleven. Additionally among girls participants they observed anatomical changes in lumbar spine. Young non-athletes practiced non-organized activity less than 2 times per week and athletes practiced sports in average 4.5 years before baseline, for at least 2 times per week. After 3 years of sports practice and competitions, it is showed that athletes were as twice as more fragile than non-athletes; acute spine injury occurred in 68% of cases during own sport event. Personal contact and pushing to the edge of the ring were the most often reported causes of low back pain by ice hockey players. Falling during game was a main cause of low back pain by young soccer players. Girl gymnasts incited spine injuries during landing on floor or jumping off or on gymnastics apparels. Figure ice-skaters were more vulnerable when falling down to the floor. These overload events occurred more frequently within girls’ athletes. MRI observations show more degenerative changes of vertebral endplates and discs with higher risk for disc protrusion, mostly between L4-L5 and L5-S1 region. However Purcell and Micheli [8] observed rare occurrences of disc degeneration by young athletes. All authors agree that repetitive minor trauma lead to spine fragility and higher risk for ring aphophysis [7,8] or spondylolysis or spondylolisthesis [16].

Young athletes are exposed to a wide range of factors that could provoke low back pain during sports’ carrier, thus in further part some of this risk factors were detailed.

Risk factors of sports on low back pain
Some evidences [17–20] expose that certain sport disciplines could cause low back pain because of high impact and high amount of repetitions, specially in sagittal (flexion-extension) and transversal (rotation) plane or in a combination of both (torsion). Risk factors are not only a type of discipline and biomechanical characteristics but also spine fragility during growth period, high volume of physical training, frequent level of sport practice and competitions with neglected time for recuperation and regeneration as well insufficient technique and more fragile personality that expose young athlete to musculoskeletal injuries and increased risk to develop low back pain [8,15,20]. Recently it is also showed that a genetic predisposition plays an important role in low back pain [5].

i) A type of discipline and biomechanical characteristics
As mentioned in previous paragraph every sports discipline produces different loading forces on the spine and vertebral discs. Every individual reacts differently on these forces; furthermore has different capacity to absorb applied forces what depends also from individual morphological composition and maturity [15,20]. Actually applied forces on the spine could be classified in three larger groups: (i) dynamic, (ii) static and (iii) axial. The first type of force is present in most of sports and could be seen in sports like tennis, golf or football. Static load force appears more often during speed skating or cycle. Axial forces are rare and more typical for weight lifting sports [15].

Understanding of biomechanics of spine and characteristics of movement of different sports helps to treat efficiently low back pain and prevent further occurrences. For example in team sports, as soccer, rugby or volleyball; body contact and high impact of landing are frequent causes for more traumatic and acute injuries [8]. Corporal expression sports - as artistic gymnastics, rhythmic, dancing, figure skating, etc - demand repetitive movement and high range of motion of trunk in sagittal or transversal plane [7,8,15,20]. Endurance sports like cross-country skiing with more forward flexion or rowing with backward extension will provoke more repetition loadings on the spine [21]. Corporal expression and endurance sports provoke more overuse injuries [8]. Orienteering or walking are sports disciplines with no or very little specific loading [21,22].

ii) Growth period
Through the life cycle low back pain progress and at different ages [23] causes different physiological changes [24]. The spine reaches maximum growth around 12 years by girls and 14 years by boys (Purcell and Micheli 2009, ref 13). It seems that this period of growing spine in pre-adolescence and adolescence is particularly fragile [8]. During this period, spine hard tissue (bones) overpasses soft tissues (ligaments and muscles) what could lead in muscles imbalance and higher risks for structural injuries, particularly of posterior elements of the spine [8,25]

iii) High amount of physical training
In 10-years longitudinal study Foss et al [21] compared low back pain of former cross-country skiers, rowers and orienteers, aged at the baseline 22. Authors observe that a high quantity of training in previous years and past occurrences of low back pain were more predictable for low back pain than the years of repetitive loading forces of flexion or extension movements in endurance sports. For example athletes practicing sports for more than 9.57 hours per week (equal to 550 hours per year) were more exposed to low back pain than those practicing 3.44 hours per week (equal to 200 hours per year). Rowers were most exposed to apparition of low back pain and after 10 years were looking for less physically demanding job, ask more often for a medical assistance and to adaptation of their work place.

Based on previously mentioned 3-year longitudinal study, Kujala et al [26] reported training hours of 11-years old athletes and compared boys and girls training hours one year before baseline and during intervention at 1st, 2nd, 3rd year of follow-up. In average boys playing ice hockey or soccer trained 3.77 hours per week less than girls practiced gymnastics or figure skating. Figure skating athletes spent 9.77 hours per week on training. At 1st year of follow-up they attain a peak with 11.57 hours per week and 3rd year their training quantity decrease for 4.86 hours per week. In the contrary ice-hockey players, gymnasts and figure skaters decrease amount of hours per week at 1st year of follow-up.

Moreover in a cross-sectional study of Sato et al [27] shown that a high weekly amount of sports practice have negative effect on low back pain among Japanese school children, aged between 9 and 15 years. At 9 years average of observed sports practice is 6.6 hours and at age of 15 this amount doubled to 12.2 hours per week. Weekly average time of sports practice is 9.8 hours. The authors report that participants practicing for a longer time are two times more exposed to low back pain.

All studies demonstrate that higher weekly dose of physical activity could be important risk factor for appraisal of low back symptoms. Whatever higher frequency of risk factors earlier in childhood could lead to more complex pain symptoms later in adulthood and present higher risk for chronicity [17–20]. Actually combination of moderate, physical activities based on power, endurance, flexibility and coordination exercises, practiced between 1 - 2.5 hours per week has positive impacts on low back pain [28]. Thus correlation between physical activity and low back pain seems to be optimal in the middle part of U shape.

Conclusion
The relationship between physical activity and low back pain is based on contradictory evidences. U shape relation between both variables of over active or inactive life-style lead by predisposed young individuals to a higher risk for low back pain [5,15,16]. Contradictory evidences depend not only from definition of both variables and use of measurement methods [16], but also from individual perception of pain (varies among age), maturity as well differences’ in socio-cultural backgrounds [29]. Multidimensional relation of this parameters’ should be taken into account, especially in the studies that are based on a population of children or adolescents [29].

In this analysis most frequent risk factors that provoke low back pain in young athletes were exposed within objective to review and improve earlier recognition of low back pain problematic and help to apply best evidence based solutions. Recommendations would be to control the amount of physical exercise and equalize time of overuse with sufficient time of recuperation [15], combine the main sports discipline with other sport, for example cross-country skiing with biking [30] or have individual strength programme; for example like rowers that strengthen multifidus muscles [31], etc.

In conclusion biomechanical and functional understanding of sports discipline [20], knowledge about risk factors, low back pain evolution and history as well taking in account complaints about low back pain would help young athletes to prevent low back pain and avoid aggravation of symptoms in adulthood [17,18,18,19].

References

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Annex

Table 1:
|Author |Wedderkopp et al |
|Year |2009 |
|Type of study |3-yr longitudinal, prospective cohort |
|Aim |PA in childhood, LBP in early adolescence |
|Population |School children |
|Number (n) |265 |
|Gender |B |
|Group (n) |G |
|Age at B (yr) | |
| |124 |
| |141 |
| | |
| |≅ 9 |
| | |
|Instrument of |MTI – accelerometer |
|measurement |Structured interview about BP at B |
|Outcome |1-month period prevalence of BP |
|Results |BP observed during 3-yr |
| |PAA: ( 27% |
| |LB: ( 46% |
| |MB:( 25 % |
| |More than one region: ( 58% |
| |PA measured at B and observed from childhood to early adolescence |
| |HPA: 34% ≅ 36 min/day |
| |MPA: 33% ≅ 15.2 min/day |
| |LPA: 33% ≅ 4.4 min/day |
|Conclusion |LPA children ( probability of PPA, LBP, MB 3-yr later |
| |LPA 68% probability for LBP and ( in odds of having LBP 3-yr later |
| |HPA protective factor |
| |Treatment with PA - WHO recommendations are at least 30 min/day |
| |Negative effect of specific sports (repetitive minor trauma could cause spondylolysis and |
| |spondylolisthesis) |

Legend: B-baseline; PAA-pain present anywhere; BP-back pain; MBP-mid back pain; LBP-low back pain; yr-year; B-boys; G-girls; PA-physical activity; HPA-high physical activity; MPA-mid physical activity; LPA-low physical activity.

|Author |Kujala et al |
|Year |1996 |
|Type of study |3-y longitudinal |
|Aim |LBP, Anatomic changes, Loading injuries |
|Population |Non athletes (NA) : athletes (A) |
|Number (n) |98 (33 NA, 65 A) |
|Gender |B |
|Group (n) |G |
|Age at B (yr) | |
| |16 NA, 34 A |
| |17 NA, 31 A |
| | |
| |≅ 11.9, 11.9 |
| |≅ 11.9, 11.7 |
| | |
|Non-Athletes |Recreational sports sporadically |
| |≤ 2*/week |
| Girls (n) |16 included in Lx MRI study at B-FU |
|Athletes | |
| Training |≥ 2*/week, for 2-yr |
| |B |
| |G |
| | |
| |17 ice-hockey |
| |17 ice-skating |
| | |
| |17 soccer |
| |14 gymnasts |
| | |
| Intervention |Strength training |
| |Individual training with different jumps |
| | |
| Girls (n) |27 included in Lx MRI study at B-FU |
|Instrument of |Questionnaire |
|measurement |MRI of lumbar spine (Lx) |
|Outcome |Occurrence of LBP and anatomic changes |
|Results |LBP |
| |at 3-yr FU more than 1w: 45% A, 18% NA |
| |at 2-yr of FU: 17% A, 3% NA |
| |at each of 3-yr: 3% A |
| |BP lasting more than 1 month: 20% A, 9% NA |
| |Acute LBP at 3-yr FU |
| |19: 8 BA, 7 GA, 4 NA ( 68% occurred at own sport event |
| |Raisons |
| |GA: ice skating – falling on buttock; gymnastics – dismount |
| |BA: hockey – tacking against rink board; soccer – falling during a game |
| |MRI |
| |43 (GA+GNA) ( 37% abnormalities: 10 A, 6 NA |
| |Number of cases after 3-yr FU |
| |DD: ( 11 (7 A, 4 NA) |
| |DP: ( 5 (4 A, 1 NA) |
| |VE: ( 2 (3 A) |
| |Most often presented (N) |
| |L5-S1: 8 |
| |L4-L5: 7 |
| |L1-L2: 4 |
| |New acute LBP 5 G (2 figure skaters, 3 gymnasts) ( ring apophysis |
|Conclusion |Certain sports demand extreme movements and apply high forces on the spine that is in adolescence |
| |at the time of growth very sensible. Overload can lead to the soft tissue injuries or to acute LBP |
| |and could later in adulthood provoke higher exposure to LB problems as well higher risk of spine |
| |degeneration. |

Legend: N-number; B-baseline; FU-follow-up; LBP-low back pain; BP-back pain; yr-year; B-boys; G-girls; A-athletes; NA-non-athletes; BA-boy athletes; GA-girl athletes; GNA-girl non-athletes; DD-disc degeneration; DP-disc protrusion or prolapse; VE-vertebral endplate changes;