The Science

The Science

Groundbreaking Study:
In a recent joint study backed by the National Osteoporosis Foundation and the International Osteoporosis Foundation, it was found that Multiple-of-Body weight Axial Bone loading creates an osteogenic adaptation in which bones actually increase in density. They found that the Bone Mineral Density increased an average of 7.02% in the hip and 7.73% in the spine after one year. By contrast, clinical trials of the drug Boniva found gains of 3.1% in the hip and 6.4% in the spine over a 3 year period. This is more than a 3 fold improvement without any of the side effects!  [FULL STUDY]
Related Clinical Evidence
Mechanostat Theory:
The Mechanostat Theory describes the way in which mechanical loading influences bone structure by changing the mass (amount of bone) and architecture (its arrangement) to provide a structure that resists habitual loads with an economical amount of material. Looking at the graph to the right you can see as the Mechanical Stimulus (Load) increases bone begins to form. Additional research along these lines have been documented by (Hong and Wang 2018, Frost 2003, Burr 1998, Burr 1997)
Maximum Force Generation:
NASA research shows that the various biomechanical angles of the body allow for changes in strength capabilities.  They found that the Optimal Biomechanical Angle for the chest press was at 80% extension.  This optimal biomechanical angle is utilized when doing the Chest Press on the ReGenesis device.  The device is specifically adjusted the user will be able to produce the most force for the upper shoulder regions.  (Human Performance Capabilities NASA-STD-3000)
Maximum Force Generation Continued:
NASA took it a step further to show how strength changes through the body's various biomechanical  angles.  Looking at the graph you can see that 5 various biomechanical angles of the knee and thighs were tested to find optimal position with the most strength.  The 5 biomechanical positions had varying degrees of knee movement from 80 degrees to 180 degrees.   The results showed that the leg strength was greatest when the hips joint angle was between 15-19 degrees, while the knee angle was around 150-160 degrees.  This supports the above findings that showed the maximum force generated for the chest press was when the user was at 80% extension.  
Safely Achieve Maximum Loading:
In addition, NASA research also showed that there are various torque forces experienced at the joints for different types of applied forces.  Looking at the graph you can see that 5 various forces were applied through a range of motion from 90 degrees to 10 degrees  (Isometric, Isokinetic 36 deg/sec, Isokinetic 108 deg/sec, Isokinetic 180 deg/sec).  They then measured the joint torque at each angle.  This research helps to support the principle that you can safely load a maximum amount of force at specific joint angles to ensure the users safety.  This data shows that the “Optimal safe ROM” of the knee occurs with less than 150° of knee extension.
So What Does It All Mean?
By combining all these theories and superimposing their optimal graph curves (Yellow Line ----), we can see the underlying principle that certain biomechanical movements can regenerate soft tissues in a safe manner.
By overlaying NASA's Optimal Strength Curve for the hip and knee (20° Knee & 15-19° Hip) with NASA's Optimal Joint Torque Angle Curve  for the knee we find an area of movement where there is the greatest amount of force production with a very low joint torque.  Basically this is stating for movements like the leg press and chest press that at 80-90% extension we are the strongest with the least joint torque.  We call this this area the Optimal Loading Zone.   

If we then overlay the bone remodeling theory Mechanostat Curve you can see the red line overlaps into the Optimal Loading Zone.  Together these curves show that the body has the potential to safely place high loads upon itself and the result is  the regeneration of soft tissues.  

We refer to this sweet spot as the ReGenesis Zone.  This principle can be transitioned to other movements of the body. 
Additional Clinical Evidence
Osteogenic loading (OL) is a rehabilitative medicine method with a goal of improving bone density and prevent bone fracture. This can be seen as a brief, intensive resistance exercise for bone health. The basis of osteogenic loading stems from Wolff's law, which shows that the force or loading on bone through its axis, can stimulate the bone's natural function of increasing in density. Further study has shown that greater loads on bone can stimulate a greater effect of the body to respond and increase the density of bone, and can show immediate effects in the body via blood testing showing bone turnover markers. This high level of loading on bone would typically be seen in high-impact activity, which is not practical for therapy given the risk of injury potential. OL is an outpatient therapy that is typically used with ambulatory individuals who are able to engage in resistance exercise. Loading/exercise for bone density preservation and improvement is supported by bone health societies and organizations, including the International Osteoporosis Foundation, the National Osteoporosis Foundation, the National Osteoporosis Society of the United Kingdom, and the World Health Organization.

Harold m Frost 2003 - Bone's Mechanostat - Anat Rec A Discov Mol Cell Evol Biol. 2003 Dec;275(2):1081-101. doi: 10.1002/ar.a.10119. 
Abstract: The still-evolving mechanostat hypothesis for bones inserts tissue-level realities into the former knowledge gap between bone's organ-level and cell-level realities. It concerns load-bearing bones in postnatal free-living bony vertebrates, physiologic bone loading, and how bones adapt their strength to the mechanical loads on them. Voluntary mechanical usage determines most of the postnatal strength of healthy bones in ways that minimize nontraumatic fractures and create a bone-strength safety factor. The mechanostat hypothesis predicts 32 things that occur, including the gross anatomical bone abnormalities in osteogenesis imperfecta; it distinguishes postnatal situations from baseline conditions at birth; it distinguishes bones that carry typical voluntary loads from bones that have other chief functions; and it distinguishes traumatic from nontraumatic fractures. It provides functional definitions of mechanical bone competence, bone quality, osteopenias, and osteoporoses. It includes permissive hormonal and other effects on bones, a marrow mediator mechanism, some limitations of clinical densitometry, a cause of bone "mass" plateaus during treatment, an "adaptational lag" in some children, and some vibration effects on bones. The mechanostat hypothesis may have analogs in nonosseous skeletal organs as well. Copyright 2003 Wiley-Liss, Inc.
 
A Ram Hong and Sang Wan Kim 2018 - Effects of Resistance on Bone Health - Endocrinol Metab (Seoul). 2018 Dec; 33(4): 435–444. Published online 2018 Nov 30. doi: 10.3803/EnM.2018.33.4.435
Abstract The prevalence of chronic diseases including osteoporosis and sarcopenia increases as the population ages. Osteoporosis and sarcopenia are commonly associated with genetics, mechanical factors, and hormonal factors and primarily associated with aging. Many older populations, particularly those with frailty, are likely to have concurrent osteoporosis and sarcopenia, further increasing their risk of disease-related complications. Because bones and muscles are closely interconnected by anatomy, metabolic profile, and chemical components, a diagnosis should be considered for both sarcopenia and osteoporosis, which may be treated with optimal therapeutic interventions eliciting pleiotropic effects on both bones and muscles. Exercise training has been recommended as a promising therapeutic strategy to encounter the loss of bone and muscle mass due to osteosarcopenia. To stimulate the osteogenic effects for bone mass accretion, bone tissues must be exposed to mechanical load exceeding those experienced during daily living activities. Of the several exercise training programs, resistance exercise (RE) is known to be highly beneficial for the preservation of bone and muscle mass. This review summarizes the mechanisms of RE for the preservation of bone and muscle mass and supports the clinical evidences for the use of RE as a therapeutic option in osteosarcopenia.

David B Burr 1, A G Robling, C H Turner 2002 - Effects of Biomechanical Stress on Bones in Animals - Bone. 2002 May;30(5):781-6. doi: 10.1016/s8756-3282(02)00707-x.
Abstract: The signals that allow bone to adapt to its mechanical environment most likely involve strain-mediated fluid flow through the canalicular channels. Fluid can only be moved through bone by cyclic loading, and the shear stresses generated on bone cells are proportional to the rate of loading. The proportional relation between fluid shear stresses on cells and loading rate predicts that the magnitude of bone's adaptive response to loading should be proportional to strain rate. For lower loading frequencies within the physiologic range, experimental evidence shows this is true. It is also true that the mechanical sensitivity of bone cells saturates quickly, and that a period of recovery either between loading cycles or between periods of exercise can optimize adaptive response. Together, these concepts suggest that short periods of exercise, with a 4-8 h rest period between them, are a more effective osteogenic stimulus than a single sustained session of exercise. The data also suggest that activities involving higher loading rates are more effective for increasing bone formation, even if the duration of the activity is short.

David Burr 1997 - Muscle Strength, Bone Mass, and Age-Related Bone Loss - Journal Of Bone & Mineral Research V12, Num 10.
Overview: 
THE EFFECTS OF DISUSE, or conversely, of elevated physical activity on muscle strength and bone mass are well known. Disuse causes muscle wasting and bone loss; physical activity increases muscle strength and bone mass. The association between muscle strength and bone mass is therefore clearly established, although neither the dominant effect of muscle on bone mass, nor the cause and effect relationship is established by these simple correlations alone. Frost proposes that “voluntary muscle forces … dominate a bone's postnatal structural adaptations to mechanical usage, modified … by body weight and one's voluntary physical activity.”

Wolfs Law by Dr. Julius Wolf: Bone adapts to the loads under which it is mechanically placed.
Overview: 
Wolff's law, developed by the German anatomist and surgeon Julius Wolff (1836–1902) in the 19th century, states that bone in a healthy person or animal will adapt to the loads under which it is placed. If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading. The internal architecture of the trabeculae undergoes adaptive changes, followed by secondary changes to the external cortical portion of the bone,[4] perhaps becoming thicker as a result. The inverse is true as well: if the loading on a bone decreases, the bone will become less dense and weaker due to the lack of the stimulus required for continued remodeling. This reduction in bone density (osteopenia) is known as stress shielding and can occur as a result of a hip replacement (or other prosthesis).[citation needed] The normal stress on a bone is shielded from that bone by being placed on a prosthetic implant.

David's Law by Dr. Henry Davis: Soft tissue adapts to loads under which it is mechanically placed.  
Overview:
Davis's law is used in anatomy and physiology to describe how soft tissue models along imposed demands. It is the corollary to Wolff's law, which applies to osseous tissue. It is a physiological principle stating that soft tissue heal according to the manner in which they are mechanically stressed. It is also an application of the Mechanostat model of Harold Frost which was originally developed to describe the adaptational response of bones; however – as outlined by Harold Frost himself – it also applies to fibrous collagenous connective tissues, such as ligaments, tendons and fascia. The "stretch-hypertrophy rule" of that model states: "Intermittent stretch causes collagenous tissues to hypertrophy until the resulting increase in strength reduces elongation in tension to some minimum level". Similar to the behavior of bony tissues this adaptational response occurs only if the mechanical strain exceeds a certain threshold value. Harold Frost proposed that for dense collagenous connective tissues the related threshold values are around 23 Newton/mm2 or 4% strain elongation.

Tobias & Gould 2014 - Physical Activity and Bone: May The Force Be With You - Frontiers in Endrocrinology 03 Marcy 2014. doi: 103389/fendo.2014.00020
Abstract:
Physical activity (PA) is thought to play an important role in preventing bone loss and osteoporosis in older people. However, the type of activity that is most effective in this regard remains unclear. Objectively measured PA using accelerometers is an accurate method for studying relationships between PA and bone and other outcomes. We recently used this approach in the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine relationships between levels of vertical impacts associated with PA and hip bone mineral density (BMD). Interestingly, vertical impacts >4g, though rare, largely accounted for the relationship between habitual levels of PA and BMD in adolescents. However, in a subsequent pilot study where we used the same method to record PA levels in older people, no >4g impacts were observed. Therefore, to the extent that vertical impacts need to exceed a certain threshold in order to be bone protective, such a threshold is likely to be considerably lower in older people as compared with adolescents. Further studies aimed at identifying such a threshold in older people are planned, to provide a basis for selecting
exercise regimes in older people which are most likely to be bone protective.

Abstract:
High-impact exercise is known to be beneficial for bones. However, the optimal amount of exercise is not known. The aim of the present study was to evaluate the association between the intensity of exercise and bone mineral density (BMD). We performed a 12-month population-based trial with 120 women (aged 35-40 years) randomly assigned to an exercise group or to a control group. The intensity of the physical activity of 64 women was assessed with an accelerometer-based body movement monitor. The daily activity was analyzed at five acceleration levels (0.3-1.0 g, 1.1-2.4 g, 2.5-3.8 g, 3.9-5.3 g, and 5.4-9.2 g). BMD was measured at the hip, spine (L1-L4), and radius by dual-energy x-ray absorptiometry. The calcaneus was measured using quantitative ultrasound. Physical activity that induced acceleration levels exceeding 3.9 g correlated positively with the BMD change in the hip area (p<0.05-0.001). L1 BMD change correlated positively with activity exceeding 5.4 g (p<0.05) and calcaneal speed of sound with the level of 1.1-2.4 g (p< 0.05). Baseline BMD was negatively associated with the BMD change at the hip. The intensity of exercise, measured as the acceleration level of physical activity, was significantly correlated with BMD changes. Bone stimulation is reached during normal physical exercise in healthy premenopausal women. In the hip area, the threshold level for improving BMD is less than 100 accelerations per day at levels exceeding 3.9 g.

Abstract:
Whether a certain level of impact needs to be exceeded for physical activity (PA) to benefit bone accrual is currently unclear. To examine this question, we performed a cross-sectional analysis between PA and hip BMD in 724 adolescents (292 boys, mean 17.7 years) from the Avon Longitudinal Study of Parents and Children (ALSPAC), partitioning outputs from a Newtest accelerometer into six different impact bands. Counts within 2.1 to 3.1g, 3.1 to 4.2g, 4.2 to 5.1g, and >5.1g bands were positively related to femoral neck (FN) BMD, in boys and girls combined, in our minimally adjusted model including age, height, and sex (0.5–1.1g: beta ¼ 0.007, p ¼ 0.8; 1.1–2.1g: beta ¼ 0.003, p ¼ 0.9; 2.1–3.1g: beta ¼ 0.042, p ¼ 0.08; 3.1–4.2g: beta ¼ 0.058, p ¼ 0.009; 4.2–5.1g: beta ¼ 0.070, p ¼ 0.001; >5.1g: beta ¼ 0.080, p < 0.001) (beta ¼ SD change per doubling in activity). Similar positive relationships were observed between high-impact bands and BMD at other hip sites (ward’s triangle, total hip), hip structure indices derived by hip structural analysis of dual-energy X-ray absorptiometry (DXA) scans (FN width, cross-sectional area, cortical thickness), and predicted strength (cross-sectional moment of inertia). In analyses where adjacent bands were combined and then adjusted for other impacts, high impacts (>4.2g) were positively related to FN BMD, whereas, if anything, moderate (2.1–4.2g) and low impacts (0.5–2.1g) were inversely related (low: beta ¼ 0.052, p ¼ 0.2; medium: beta ¼ 0.058, p ¼ 0.2; high: beta ¼ 0.137, p < 0.001). Though slightly attenuated, the positive association between PA and FN BMD, confined to high impacts, was still observed after adjustment for fat mass, lean mass, and socioeconomic position (high: beta ¼ 0.096, p ¼ 0.016). These results suggest that PA associated with impacts >4.2g, such as jumping and running (which further studies suggested requires speeds >10 km/h) is positively related to hip BMD and structure in adolescents, whereas moderate impact activity (eg, jogging) is of little benefit. Hence, PA may only strengthen lower limb bones in adolescents, and possibly adults, if this comprises high-impact activity. 

Abstract: 
The purpose of this randomized controlled study was to assess the effects of high-impact exercise on the bone mineral density (BMD) of premenopausal women at the population level. Materials and methods: The study population consisted of a random population-based sample of 120 women from a cohort of 5,161 women, aged 35 to 40 years. They were randomly assigned to either an exercise or control group. The exercise regimen consisted of supervised, progressive high-impact exercises three times per week and an additional home program for 12 months. BMD was measured on the lumbar spine (L1–L4), proximal femur, and distal forearm, by dual-energy X-ray absorptiometry at baseline and after 12 months. Calcaneal bone was measured using quantitative ultrasound. Results: Thirty-nine women (65%) in the exercise group and 41 women (68%) in the control group completed the study. The exercise group demonstrated significant change compared with the control group in femoral neck BMD (1.1% vs −0.4%; p=0.003), intertrochanteric BMD (0.8% vs −0.2%; p=0.029), and total femoral BMD (0.1% vs −0.3%; p=0.006). No exercise-induced effects were found in the total lumbar BMD or in the lumbar vertebrae L2–L4. Instead, L1 BMD (2.2% vs −0.4%; p=0.002) increased significantly more in the exercise group than in the control group. Calcaneal broadband ultrasound attenuation showed also a significant change in the exercise group compared with the control group (7.3% vs −0.6%; p=0.015). The changes were also significant within the exercise group, but not within the control group. There were no significant differences between or within the groups in the distal forearm. Conclusions: This study indicates that high-impact exercise is effective in improving bone mineral density in the lumbar spine and upper femur in premenopausal women, and the results of the study may be generalized at the population level. This type of training may be an efficient, safe, and inexpensive way to prevent osteoporosis later in life.
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