The Sports Physician’s Point of View
The view that simply taking care is the best method of preventing damage to
joint cartilage is wrong. Patho-physiological studies have shown that welldosed,
undulating stress stimulation in the form of pressure and relaxation is
necessary for the supply of nutrients to blood vessel-free cartilage from the
extra-chondral synovia or lymph vessels and for the elimination of metabolic
waste from cartilage.
Dosed stress is apparently a stimulus for the neogenesis of the cartilage
It has also been established, however, that biomechanical strains on the joints from a variety of different causes can lead to trophic disturbance and cartilage damage. However, to interpret this as a warning against sporting activities would be wrong. In fact, a sedentary lifestyle is an invitation to joint problems. Although many scientifically unfounded claims have been made concerning the osteoarthritis risk to endurance athletes such as marathon runners, racing cyclists, cross-country skiers and walkers, there is in fact no additional risk. Long-distance runners who in the course of their careers cover 150,000 – 200,000 km or racing cyclists who cover 30,000 km in training runs show no increased incidence to osteoarthritis in the knee or hip joints providing there is no basic axial damage. There is in fact evidence showing that such endurance athletes suffer less with respect to osteoarthritis than the normal population – always providing there is no axial damage, biomechanical problems or trauma.
It has been observed that osteoarthritis of the patella frequently occurs in weight lifters; however, this does not contradict what has been said above. In such cases it is assumed that the massive short-term pressure exerted on cartilage in this type of sport dehydrates the cartilage tissue; it becomes more vulnerable and the risk of micro-trauma is increased. Apparently, it is not the stress itself that causes lesions in the cartilage tissue but more the repeated micro-traumatic events in the cartilage matrix. “It is not so much sports activity itself but the resulting trauma that is the main cause of joint damage” . Thus, the risk involved results from repeated biomechanical problems, weak muscles and joint misalignment on the part of untrained persons carrying out sports activities, from already present joint anomalies (e.g. false axial positions), inadequate loosening up prior to high-performance sports activities or subsequent to non-recognized or untreated trauma.
Metabolic disturbances (including adiposity) and neurological defects also apparently reduce cartilage stability; the result is that in such patients there is a potentiated risk of osteoarthritis in the case of biomechanical stress, possibly also due to local loss of fluid.
However, it is not only power and endurance sports that can cause multiple and unrecognized micro-trauma on the surface of the cartilage; all sports activities involving movement can bring about the condition. If the body is abruptly stopped at maximum speed, e.g. by accident or collision, the cartilage and joint surfaces can rupture; these then become scar tissue made up of inferior cartilage. Practical experience shows that the administration of collagen preparations may have a favorable influence on cartilage regeneration; thus, sports physicians often recommend the administration of collagen hydrolysate as a preventive measure for those sports activities involving an increased risk of micro-trauma.
The risk of traumatic cartilage damage varies according to the type of sport and the joints involved . Examples of early osteoarthritis as a result of sports trauma are: • Toe joints: almost 50% of ex-football players over 50 have severe osteoarthritis of the toe joints.
• Ankles: 48% of high-jumpers and 85% of ballet dancers have some evidence of osteoarthritis of the ankles.
• Femur patella: In one report 100% of football players and 90% of weightlifters have early osteoarthritis of the femur patella joint. • Lumbar vertebrae: 100% of javelin throwers and 90% of gymnasts and divers have problems with their lumbar vertebrae. • Shoulder: field athletes (e.g. throwers) and basketball players have frequent problems with the shoulder joint.
• Elbow joints: 90% of weight-lifters, javelin throwers and boxers have trouble with their elbow joints.
Even those sports that are regarded as being joint-friendly, e.g. swimming (including swimming as training for other high-performance sports) is not entirely harmless. In the breast stroke e.g. the medial structure of the knee joint may be traumatized and over-stressed , even if this particular risk is much lower than for the other sports mentioned above.
From the sports medicine point of view, the greater risks with respect to joint stability and firmness of joint cartilage are under-stressed joints subjected to too little activity . This is because inadequate muscular stability undoubtedly represents a risk of osteoarthritis.
The correlation in this respect is demonstrated by studies carried out in my laboratory on the isokinetic and isometric development of power under the administration of collagen hydrolysate . This study was carried out between February and September 1999 on a total of 567 persons screened according to specific exclusion criteria. In the final assessment after 14 weeks, 176 volunteers which met American College of Rheumatology (ACR) criteria for osteoarthritis of the knee were considered. In the 14-week, randomized, prospective, double-blind and placebo-controlled study, collagen-enriched food or placebo were administered. At the beginning of the study, after 8 weeks and at the end of the study, a 6-minute walking test and the time required for a 50-foot walking stretch were carried out; however, these proved to be too insensitive. Pain levels, radius of movement and degree of mobility produced positive results in the group receiving hydrolyzed collagen. It was surprising to note that of the low-level and slight degree of side effects, the placebo group indicated more symptoms such as diarrhea, headache, nausea etc. than the study group with collagen hydrolysate.
Apart from the predominantly joint parameters employed, a number of isokinetic and isometric measurements were carried out to determine leg power (Biodex Multi-Joint System B 2000™). In the assessment, the 6 isokinetic leg power measurements showed significant increase between weeks 0 and 14 (but not from weeks 0 to 8). There was no such significance in the placebo group; in fact, in part there was a worsening. In the case of the isometric measurements, there was no significance between the groups; there was, however, a positive trend towards the collagen hydrolysate volunteers.
These results indicate the additional stimulating effect of collagen hydrolysate on the joint. These findings suggest that hydrolyzed collagen may improve joint cartilage. Using this mechanism, it was possible to explain the positive effects of dosed physical and sports activity in the prevention of osteoarthritis. Clinical and sports-medical data on the benefits of collagen hydrolysate in sports nutrition have been available for a number of years. The influence of orally administered collagen hydrolysate on the amino acid concentration in the blood of performance athletes has been regarded as proven for a decade.
BEUKER et al.  demonstrated in a single-blind, randomized and placebocontrolled study carried out on sports students at the University of DüsseIdorf, Germany, over a period of 4.5 months that, under stress power training (3 x 1.5 h per week), the daily administration of 10 g collagen hydrolysate changed the concentration of the amino acids in the blood stream. In the study group e.g. in a total of 6 control measurements, there was a highly significant increase in the concentrations of glycine, proline and hydroxyproline. In the placebo group, under the same training conditions and same meals (no foods containing gelatine), there was no such change in the amino acid profile.
Further studies confirm these results in various groups of patients. The benefits established on the administration of collagen hydrolysate were confirmed by sports-medical assessment methods whilst those on placebo obtained no benefits.
Bone Structure & Role of Collagen in Bones